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


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