/in/foo.cc:1:1: error: 'include' does not name a type
 include <iostream>
 ^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:7:5: error: 'cin' was not declared in this scope
     cin >> n >> m;
     ^~~
/in/foo.cc:16:23: error: 'abs' was not declared in this scope
         if(abs(s1 - s2) == m) sum ++;
                       ^
/in/foo.cc:18:5: error: 'cout' was not declared in this scope
     cout << sum / 2 << endl;
     ^~~~
/in/foo.cc:18:24: error: 'endl' was not declared in this scope
     cout << sum / 2 << endl;
                        ^~~~