P!nk notches her fourth No. 1 on the on the Billboard Hot 100, as "Just Give Me a Reason," featuring fun.'s Nate Ruess, rises 3-1. Justin Timberlake and Demi Lovato, meanwhile, return to the top 10 with "Mirrors," and "Heart Attack," respectively, and PSY gallops onto the chart at No. 12 with "Gentleman," which has already set YouTube views records following its release last week.