/in/foo.cc: In function 'int main()':
/in/foo.cc:32:21: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
  while(scanf("%d",&a)){
                     ^
/in/foo.cc:29:16: warning: unused variable 'b' [-Wunused-variable]
  long long n,a,b,i;
                ^
/in/foo.cc:29:18: warning: unused variable 'i' [-Wunused-variable]
  long long n,a,b,i;
                  ^