func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long int n, ans = 0;     cin >> n;     string x;     cin >> x;     for (long long int i = 0; i < x.length(); i++) {       if (x[i] ==  0  || x[i] ==  2  || x[i] ==  4  || x[i] ==  6  ||           x[i] ==  8 ) {         ans += (i + 1);       }     }     cout << ans;   }   