Savan Kotecha wrote the lyrics for `` Na Na Na '' and `` Live While We 're Young '' .
`` Kotecha has written such hits as Britney Spears ' `` '' If U Seek Amy '' '' and `` '' I Wan na Go '' '' , Usherï¿½s `` '' DJ Got Us Fallin ' in Love '' '' and One Direction 's `` '' What Makes You Beautiful '' '' , `` '' Na Na Na '' '' and `` '' Live While We 're Young '' '' . ''
Savan Kotecha