/in/foo.cc: In function 'int main()':
/in/foo.cc:5:2: error: 'longlong' was not declared in this scope
  longlong a,b;
  ^~~~~~~~
/in/foo.cc:6:7: error: 'a' was not declared in this scope
  cin>>a;cin>>b;
       ^
/in/foo.cc:6:14: error: 'b' was not declared in this scope
  cin>>a;cin>>b;
              ^