#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int a[26];
    for(int i=0;i<26;i++){
        cin >> a[i];
    }
    string s;
    cin >> s;
    int max_height=0;
    for(int i=0;i<s.length();i++){
        if(a[s[i]-'a']>max_height){
            max_height=a[s[i]-'a'];
        }
    }
    cout << max_height*s.length();
    return 0;
}