func_code_string: #include <bits/stdc++.h>   using namespace std;   void code() {     long long n, k;     cin >> n >> k;     long long a[n];     for (long long i = 0; i < n; i++) {       cin >> a[i];     }     sort(a, a + n);     long long ans = 0;     for (long long i = 0; i < n; i++) {       if ((a[i] - a[0]) % k != 0) {         cout <<  -1  << endl;         return;       }       ans += ((a[i] - a[0]) / k);     }     cout << ans << endl;   }   signed main() { code(); }   