/in/foo.cc: In function 'int main()':
/in/foo.cc:11:11: warning: unused variable 'flag' [-Wunused-variable]
  int n, m,flag;
           ^
/in/foo.cc:12:14: warning: unused variable 'b' [-Wunused-variable]
  long long a,b,c,low;
              ^
/in/foo.cc:12:16: warning: unused variable 'c' [-Wunused-variable]
  long long a,b,c,low;
                ^
/in/foo.cc:12:18: warning: unused variable 'low' [-Wunused-variable]
  long long a,b,c,low;
                  ^