ute ▁fragment ▁which ▁she ▁performed ▁in ▁the ▁film ▁P itch ▁Per fect , ▁accomp any ing ▁herself ▁only ▁by ▁cla pping ▁and ▁t apping ▁a ▁pl astic ▁cup , ▁was ▁rem ixed ▁and ▁released ▁as ▁a ▁full - length ▁single . ▁ ▁It ▁to pped ▁the ▁AC ▁chart ▁for ▁three ▁weeks ▁before ▁being ▁disp la ced ▁by ▁K aty ▁Perry ' s ▁" Ro ar ". ▁ ▁Having ▁begun ▁with ▁a ▁Christmas ▁song ▁at ▁number ▁one , ▁the ▁year ▁ended ▁with ▁another ▁at op ▁the ▁chart , ▁as ▁Kelly ▁Clark son ' s ▁" Under ne ath ▁the ▁Tree " ▁held ▁the ▁top ▁spot ▁for ▁the ▁final ▁three ▁weeks ▁of ▁ 2 0 1 3 . ▁ ▁Chart ▁history ▁ ▁See ▁also ▁ 2 0 1 3 ▁in ▁music ▁List ▁of ▁artists ▁who ▁reached ▁number ▁one ▁on ▁the ▁U . S . ▁Ad ult ▁Contempor ary ▁chart ▁ ▁References ▁▁ 2 0 1 3 ▁Number - one ▁adult ▁contemporary ▁singles ▁United ▁States ▁Ad ult ▁Contempor ary <0x0A> </s> ▁An ▁Inter rupt ▁Request ▁Level ▁( IR QL ) ▁is ▁a ▁hardware - in dependent ▁means ▁with ▁which ▁Windows ▁prior it izes ▁interrupt s ▁that ▁come ▁from ▁the ▁system ' s ▁process ors . ▁On ▁processor ▁architect ures ▁on ▁which ▁Windows ▁runs , ▁hardware ▁generates ▁signals ▁that ▁are ▁sent ▁to ▁an ▁interrupt ▁controller . ▁The ▁interrupt ▁controller ▁sends ▁an ▁interrupt ▁request ▁( or ▁IR Q ) ▁to ▁the ▁CPU ▁with ▁a ▁certain ▁priority ▁level , ▁and ▁the ▁CPU ▁sets ▁a ▁mask ▁that ▁causes ▁any ▁other