func_code_string: #include <bits/stdc++.h>   using namespace std;   long long d[25];   int main() {     long long t;     cin >> t;     while (t--) {       long long n, s;       cin >> n >> s;       long long len = 0, sum = 0, num = n;       fill(d, d + 25, 0);       while (num > 0) {         d[++len] = num % 10;         sum += d[len];         num /= 10;       }       if (sum <= s) {         cout << 0 << endl;         continue;       }       long long cur = 0;       for (int i = len; i >= 1; i--) {         cur += d[i];         if (cur >= s) {           d[i + 1]++;           for (int j = i; j >= 1; j--) d[j] = 0;           break;         }       }       long long ans = 0;       cur = 1;       for (int i = 1; i <= len + 1; i++) {         d[i + 1] += d[i] / 10;         d[i] = d[i] % 10;         ans += d[i] * cur;         cur *= 10;       }       cout << ans - n << endl;     }     return 0;   }   