#include <iostream>
#include <string>
using namespace std;

int H[26];
string s;

int main() {
    for (int i = 0; i < 26; i++)
        cin >> H[i];
    cin >> s;

    int maxv = 0;
    for (int i = 0; i < s.size(); i++) {
        maxv = max(maxv, H[s[i] - 'a']);
    }
    cout << maxv * s.size() << endl;
}