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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int f[16];
    string s;
    for(int i = 0; i < 26; i++) cin >> f[i];
    cin >> s;
    int m = 1;
    for(int i = 0; i < s.size(); i++) m = max(m, f[s[i] - 'a']);
    cout << m * s.size() << endl;
    return 0;
}