1139A - Even Substrings - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
int main(){
   int n;
   cin >> n;
   string s;
   cin >> s;
   int ans=0;
   for(int i=0;i<n;i++){
      if((s[i]-48)%2==0){
         ans+=i+1;     
      }     
   }
   cout << ans << endl;
   return 0;
}