func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, k, sum;   string a;   int main() {     cin >> n >> k;     for (int i = (0); i < (n); i++) {       int l, r;       cin >> l >> r;       sum += (r - l + 1);     }     if (sum % k == 0)       cout << 0 << endl;     else {       int u = sum;       while (u % k) u++;       cout << u - sum << endl;     }     return 0;   }   