/in/foo.cc: In function 'int main()':
/in/foo.cc:5:15: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'int' [-Wformat=]
  scanf("%d" ,n);
               ^
/in/foo.cc:8:18: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'long long int' [-Wformat=]
   scanf("%lld" ,a);
                  ^
/in/foo.cc:5:16: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  scanf("%d" ,n);
                ^
/in/foo.cc:8:19: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
   scanf("%lld" ,a);
                   ^