#include <iostream>
#include <string>

using namespace std;

int main(){

    int a[26];
    for(int i = 0 ; i < 26 ; i++){
        cin>>a[i];
    }

    string s;
    cin>>s;

    int max_height = -1;
    for(int i = 0 ; i < s.length() ; i++){
        int c = s[i] - 'a';
        if(a[c] > max_height){
            max_height = a[c];
        }
    }

    int ans = s.length() * max_height;
    cout<<ans;

}