#include <bits/stdc++.h>

using namespace std;

int h[30];
string s;

int main (int argc, char const *argv[]) {
    for (int i = 0; i < 26; ++i) scanf("%d", h + i);
    cin >> s;    
    int n = s.size(), best = 0;
    for (int i = 0; i < n; ++i) best = max(best, h[s[i] - 'a']);
    printf("%d\n", n * best);
    return 0;
}