/in/foo.c: In function 'main':
/in/foo.c:24:16: warning: format '%lld' expects argument of type 'long long int', but argument 2 has type 'int' [-Wformat=]
     printf("%lld ", gcd(aa, bb));
                ^
/in/foo.c: In function 'gcd':
/in/foo.c:17:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^