Fixed points

#include <bits/stdc++.h>
 
#define u64 unsigned long long
using namespace std;
 
int main(){
  cin.sync_with_stdio(0);
  cin.tie(0);
  
  int tests; cin >> tests;
  while(tests--){
    u64 a, b; cin >> a >> b;
    if(b-a > 0)
      cout << b-a << endl;
    else
      cout << "-" << endl;
  }
  return 0;
}

Test 1

Verdict: WRONG ANSWER