func_code_string: #include <bits/stdc++.h>   const int MOD = 1e9 + 7;   using namespace std;   signed main() {     long long t, n;     cin >> t >> n;     long long a[n];     set<long long> s;     long long c = 0;     for (int i = 0; i < n; i++) {       cin >> a[i];     }     for (int i = 0; i < n - 1; i++) {       c += t - a[i];     }     cout << c << endl;     return 0;   }   