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

int h[26];

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    for (int i = 0; i < 26; ++i) {
        cin >> h[i];
    }
    string s;
    cin >> s;
    int mh = 0;
    for (char q: s) {
        mh = max(mh, h[q - 'a']);
    }
    cout << s.size() * mh << endl;
    return 0;
}