#include <map>
#include <set>
#include <stack>
#include <cmath>
#include <queue>
#include <vector>
#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>

using namespace std;

const int max_n = 33, inf = 1111111111;

int a[max_n];
string s;

int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    for (int i = 0; i < 26; ++i) {
        cin >> a[i];
    }
    cin >> s;
    int h = 0;
    for (int i = 0; i < s.length(); ++i) {
        h = max(h, a[s[i] - 'a']);
    }
    cout << h * s.length() << endl;
    return 0;
}