CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "catalog.aap.org",cType: 'managed',cRay: '8e711bd11eda3db3',cH: '4Mda1lncfcnhEAvz7TTmkc0ZM6HkYTJobpUI8R5myiM-1732364377-1.2.1.1-cRjz1io1s8KWvTJCr9jFjeWqKiZ4npimVkCi1zgHPi8ZMKIcCGq8XqeQb4OC5zgd',cUPMDTk: "\/?__cf_chl_tk=FyQTWVQVfN_BTK8DDJ35CfPk2wMmNWVH36jAF_gbhs8-1732364377-1.0.1.1-hjsNctYNGxMb9G8uI4HnUNGdxUNJuksAcWRUlpKYgYQ",cFPWv: 'g',cITimeS: '1732364377',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/?__cf_chl_f_tk=FyQTWVQVfN_BTK8DDJ35CfPk2wMmNWVH36jAF_gbhs8-1732364377-1.0.1.1-hjsNctYNGxMb9G8uI4HnUNGdxUNJuksAcWRUlpKYgYQ",md: "YwhJDZXcCWAbI.tGZRSGHQvk1GdQHSq0cM7dshHPjzM-1732364377-1.2.1.1-iuQe9X9a2YLL_OG91oSX.jjUw0WeRgVHKl9x7Uh_2cVLc1NdVE5gB3jgGH8rsKZvmb5osCyHzGSuFhaHQynRYtRKifw7Wt4Q9JkBJsEx2B8fJ47hiIReEKbu.NjF5PIfP4AdJZdGtsXsv12ceYdd4IV2rMAdAMQoQQ84N4.m8dJGTPz_G19Hd5_CAUeXf2Ol6CaVnGA7eZ70cA6rMUANBkpdraZqkDYyrnuvfkHFd349ifOQRc0n84l8QuMWOkmnL_Gh9llhq_D2qxEuN7LCtmFzTkYykpViElLgDt0GDehfFVwRJhOzQY8357.Sti5uyTEj3_BFUjPQxJLajcO45LvQTFY7ioUt5UN0ACEzMJ2DjZFYeiM6i5yZcPtXjA422BxwV9jyrGcKAlW_gy9QB_N_PgkhSXxmfYecrEVvj02m16sAb76zKm08jDs3gHJL04iPB4eNX6NM7L1JRx33ezJW0hqzgeNeULdKKkb.jRp0JVej7oIS6NX9gHAXfpCCav63081AQqo3NqF0rDMggeUJANxvW5c2pDuXIOVXtEKXqSax_WRX17TXejOQUcBYbUo0TfdO6o9sunV0L_Jfv5rwGZjLPaJBw0SXyN9ah2hibD6NLntaWY4lreXin3W2MW..JS1beMLXuDde9wqXv.dzQpCnFBhdIM4qJHs9VlGRBMvaWd9W8Kyaw3KKS9w20HbiDUc6PVQOLOfUL0ni7QqDEmjA2ZCaaoTBu.phs63UPHtMdXWbfHu2WXL_bW83UQaQxfRJQ0u1zegCKSaCr9AlrdJCUAy8w6J0zzYxJjQyotYKf5i0lsxhzsGTWxoG6_1sm_LekZ8zbBc5PGMBRXcXona8TCJ0vv98BbIVrPik2O.Yb59brb9aYdVgthC6g2q0_3wZVUH7NHwwqNuHIXCt1e0FZiBaUNfoAASq37MnhRxDbvlq5Jjxk4NKwz7NCzfAqeB4Xi9mDgNkGWjBzncVwbxcIGYF4o2Y0yN.oxceQp990OBZpNJ9GemPhEu2Vl_9tyqBjkeWOjKgeZ7JuLucDjHSqMmtqoKKRHuOGh9AL9t4R5wMVC292A32XSF7GLsoI17PdwrOEbCDPo1spawY0Ip_5CojwW2Kkwdz1WU9wNIt7tQF68ALcdGBlSRc2M2T2vXRnpcyd.HxNfNR2K05C2YCRkYZbBst5WBbwtefIlVOPqjusCi6PMlsYE3qux58WgoRevqakbrJ1Dx2_EphvvJ1tabKStUqkZLsCgEk1_PYByVcvIjWKa5vnuyMk1J13Aj_cUlR6srrEVe3c4WH6ngv_lkFa8JwcZnchEazcgOXNs9TEUkemOctKPMEuYJ9A7fCf43UAWDxKS2bdNvakJPldelzks3sF5rpy3oJWvVmjk7aON1GmSzsGiO9p6.fH3YGk.Qna.MeQOZeLSZaj0mY2g5HQZRCiIiLX3f9BImexnKG3bNQHvjqM.u_JRHxGxLIVT8PHfijCWaJG9QdPmWFiUKdZkTssWYfOG8dW7mLVDCfReHcYWAtAys9FaN_87KsADFDh1MgO3D25plAr1uen9La1KUxDBOw6l0GkcVaFC_3ahNfbPiqsLryECq1linKzcZW5fafuVqO1cKoIHxdZrpq0WYh4GryntwgxYj4NLHi7RbSlqC3qfHKNoj8XVOp2Ad.41_nDJtq5_SynJ_GdR3kPfv1iN4n4B4auTUNK9sd95FwxVCfr6n2li62tblSQHAoC_39fFlTIGFsJB5szEBxHmkt_wVFxFC6vp8ku7oshRS5kZ6x8xzQ_62w6zu3vmhSQyb2AWbmwcpt53D5fXaIKa1UM1AJU4VXQVPs2uDraNNS0or2cqNucoD38_kQUseh7PvXheXBQDeEMw1SFjkFPXTUEaUXPUFVEEsp3YSfNJnRIO9sqkl15RIGKgmpUmj.rv0jjuKo7n8WuNM4uDADhIQ4Oq34fuoNNVTG4VWnWLOCbZrj7QmuuMNrZlNeUnm6Pu47zyfF92T_UHvFbIO4HlCgY6EkK2tUF7YP1CXeG_8mAuMINQomWDjaV47xOAwI9p0AUSTmF10OcpHrvU0MS7Xe0Lkg8IdtNIr0N0JyopfXAQFcYrLv5FOVaxxSVJy8abJI3piB_8CJODW3WAx_p2oSSpHu66xqcl1Wksn9apKBwzkxTA.SsXH5mCi1emA56kQ9T6UOMuygKJqb4pTmVVjtNWQjhD309e83aIVVb.XSnJIIRdurRLSd75PyrQXCLxlmnniR5FwloYr3KLZiXI0VoZAp5MfGVyCrrWt0mtkdpgAK1F8z8RJS5wY83Wmp3Vnwpuav1KIAxNaw9e.o2qhOvuw_TkytKX1NQrDw.LVkvqs1ky3tnYyPYwfWO.hqw7ErzUtu3BcDys17HK19Ai8clT1goV8OaZhO5w1VNaeWPugnNz1RWUrXh6mUWV6cJyDr2YhXMq50vtdeazLPXBqo4tlPZL9HUUqvZUmb1VCGg_frA4GYIHgjGwtwT.6rG0YigO5Vbzr.D_IkJ.4MbHBY4a.6xk0EY2W5Hs9rMnUh.ycv8tVi_WrUng7Oc.geDjyvRc8jVtxhDKtT3ChNYkRqySgarLGK525oS7ivsT8VaHZPqwtYmhyRTyM3kssZTzPvAuVcfuUDB9UaaDfaB3uNPVxstYHjn2HWjQ71JLvCCqrVElpcskFmHrsXYk5tRpF3X4_ba6RcajRV9xCboLKOhs7jIoPcofEmWWbSS29cmU102Ka4wvDjWMHasjk59L7Q_b7O4Ux73gTUGu3TsrxhQoKc9gCwV6UgRmXPC4VH7yombXP9jsD51uqzIu99dAvjs5lGQIqTonyTvcU9ht2aAWHVNPVI8OWyiC9dpHrw8ypn6hgb",mdrd: "fdhQcPW4FAsU6DX96ZcD.QRlt0QjLOqQ0oS_QEA7Qm0-1732364377-1.2.1.1-m999mP3xBdCB2yxVsjGkhqfEHa92re7nYI2VafnBMjX.JTVgbtsTIX6yuMIUdanfHi_ATefFDwFBhxGDmJguwnr37ECpMlvs.UU7ESNj8CVEy8NdJX51AMCS0Pi1DAEn_r8uadFDfe69dy.DnW__c4Nf0611Izu4r7oJE6r8OrxcqxoMxLihXvNPdJC7GWIxyd00py6x2Rnxt56JhyapRpgZzp9LLZ15pyaZ1nIMh6IYQXCarbLdrWTWnBFbpNUOjHgLtMkybEcOCj1fGGPgd26N0YVPpYUegtXBuC8u.wQP3NcnP8znIgJQkkJKd9nnAD4iHtxeMmKgxXZ.iyvFzooobPQzeDiCFsQkZzkW_GFhs.tXeWuUzunvldVZNf.L4ao6zitjgqVEPLsiPY2rAp9st7EUWZiS_lfBpvttNElm9BfwoNrL1lSIv0I9gXF9REKbiN8sP6afYw7OU2xNpZsAMFXksjICxZGgxY14btQRBl82K60yK7ceSd83DZ92KaF5Sqz7odKlG1cIOFDU116l3eNxbHAUuRv9QkP.7Ya_U8cAJlannhBAqoy4We4WY93f8axOUXre8DJ4aNmBhtywmPazQIYP4DOVhnwUlezKuP8TVg8rvnA6X5CBq3uge3zwU.eU2.1DLQsDBwMeaXiwvEOlAg1kaNj7HxQOVuzBsPrkCv.LfNN5jHJ1a43LThPLl55svv8qEpVf8Ng_5aZrssyrXeAz9XfS.2N8T.HWgD8uNaWmREDSVcUv17h_ND75xU__M0SjGruUz.DFqkMUJ0XDGQJBgSUE4Ssob8qfbhR3p_aaJ1kbSa0ZzaE_6SDARzzrhfzXE54t5w3DX8PMfkWnaWoQfHG5vCj4Kl9Czd1_ZczLwuwEddCSnANhWxP0P2jqEU18JyR_lL.Ayf_fWKtwsOL7DCtkVdNtjDaWw9iLnjK8Cd5ptx0GVNUGyOklOGiqUUmqynDTu9chvzi_.PmzZdPIwEjoIInx9lD_iu_R7b02MioepqN.HFDy7H0ib7SmOmiop5JeN2OoCSAPrGN9IkJorrBfRWUc76BDfg_FjVM_E7qtoCVWMA4ArPcFm_hJtCcBNWEGmE2OIvJfnH6kIihGtu.erwJ7ZO9noWcLrOVPPSbgfFT7dhXPKxgNn1N6Agbko5.xGM4US0pzB7jfE7OqhpZbUHZZgfgsoTtaXvbbR1wr5kd3lzmS9VPP32JlGMpMcMD3brZTAEjMIs5624CjU94WqS0dGwZZ_SovnQ1fSlf5_OU1NXxuWjZ5sVqGS9HrbVULOSY4UoGb5EAtFnkn0vQyOBrNJcCmhmHhyeMA10RIcLmvOXdGEq..w3a.UYzalhVRFQ3cUkQfokvSrgc7ro07bQ_jRNvgvs_LFj8IdF99BT7EXaGJO0mVrNZ_SDgcHgJNlV4SPbc8fhNtufEQ4oLjhIWD0TF9z8R0.WgILT_ALD2j5v5sjjxb1yMwX83XxkM.2VKvjCl6XsWyGmTol7wSr2d2l446_yD8BnSZi6chqSTi.iUApf9IHqI3ZjmPL6Dml2E.sBPrHgYIwP8VZCjJKQDc5qn.YMPQlfZNPwtHlefgkw3GdEEpnKg0wJ3PkBRgZKLBEitGNB0g0qyDpP1XKjmelFcvebmHZvs9lB9Y8bgWQwmm8hlqiaAy1MRJBzlSI.1ZODcBSrDm6d5ASxXG2i7vPkDwKGHlqAZOggvot4ZzVmkOKxwdiqnnyP7XRJyGRckOw55263UhR06T3qeTP75M.wvq7RA5sN89NgKT4g1tilBSxKdjyXzm85cHQ2XxIrin41vIIqy5SmSegD146T2U2Rl_vwNz4UT6y1KyioMwyldmWruJ8DsEPfrbXVJPtu2OgoFD11lC6.biVB258MCsKsfLKBkAkkQkQGGV6.ETHxh7xS.uDcq3wHJwV.08qAz4UlJUnxJdxkRpiSG08_WKmbrmXg_TwmKr8.cNVlFG3pWu"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=8e711bd11eda3db3';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/?__cf_chl_rt_tk=FyQTWVQVfN_BTK8DDJ35CfPk2wMmNWVH36jAF_gbhs8-1732364377-1.0.1.1-hjsNctYNGxMb9G8uI4HnUNGdxUNJuksAcWRUlpKYgYQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>