func_code_string: #include <bits/stdc++.h>   using namespace std;   const long double PI = acos(-1);   const long long MOD = 1e9 + 7;   const long long INF = LLONG_MAX;   const long long SIZE = 100000;   void solve() {     long long n, s;     cin >> n >> s;     long long sum = 0, dig = 0, fir;     long long k = n;     vector<long long> v;     while (k != 0) {       long long rem = k % 10;       sum += rem;       fir = rem;       v.push_back(rem);       k /= 10;       dig++;     }     if (sum <= s) {       cout << 0 << endl;     } else {       reverse(v.begin(), v.end());       long long sum2 = 0, fin;       long long pos = -1;       for (long long i = 0; i < (long long)v.size(); i++) {         sum2 += v[i];         if (sum2 > s) {           pos = i;           break;         }       }       sum2 -= v[pos];       long long yup = -1;       for (long long i = pos - 1; i >= 0; i--) {         v[i] += 1;         sum2 += 1;         if (sum2 <= s) {           yup = i;           break;         }         sum2 -= v[i];       }       if (yup == -1) {         long long fin = pow(10, dig);         cout << fin - n << endl;       } else {         for (long long i = yup + 1; i < (long long)v.size(); i++) {           v[i] = 0;         }         long long fin = 0;         long long len = v.size() - 1;         for (long long i = 0; i < (long long)v.size(); i++) {           fin += v[i] * pow(10, len);           len--;         }         cout << fin - n << endl;       }     }   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int t = 1;     cin >> t;     while (t--) {       solve();     }     return 0;   }   