/in/foo.cc: In function 'int main()':
/in/foo.cc:21:19: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   scanf("%lld", &a);
                   ^
/in/foo.cc:18:9: warning: unused variable 'p' [-Wunused-variable]
  double p=(double)u/v;
         ^