func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int a, b;       cin >> a >> b;       if (b > a)         cout << b - a << endl;       else {         if (a % b) {           cout << a / b * b + b - a << endl;         } else           cout << 0 << endl;       }     }   }   