func_code_string: #include <bits/stdc++.h>   using namespace std;   int v[100010];   int main() {     int n, k;     scanf( %d %d , &n, &k);     int low = 1000000001;     for (int i = 0; i < n; i++) {       scanf( %d , &v[i]);       low = min(low, v[i]);     }     long long ans = 0;     for (int i = 0; i < n && ans != -1; i++) {       if ((v[i] - low) % k == 0) {         ans += (v[i] - low) / k;       } else         ans = -1;     }     cout << ans << endl;     return 0;   }   