#include <bits/stdc++.h>

using namespace std;

int h[30];

int main() {
    //ifstream cin ("Designer PDF Viewer.inp");
    //ofstream cout ("Designer PDF Viewer.out");
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    for (int i = 1; i <= 26; i++) {
        cin >> h[i];
    }
    string s;
    cin >> s;
    int maxHeight = 0;
    for (int i = 0; i < s.length(); i++) {
        maxHeight = max(maxHeight, h[s[i] - 'a' + 1]);
    }
    cout << maxHeight * s.length() << "\n";
}