#include <bits/stdc++.h>

using namespace std;

int main()
{
    int h[27], res;
    string s;
    for (int i = 0; i < 26; ++i)
        cin >> h[i];
    cin >> s;
    res = h[s[0] - 'a'];
    for (int i = 1; i < s.size(); ++i)
        res = max(res, h[s[i] - 'a']);
    cout << res * s.size() << endl;
}