#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    vector<int> h(26);
    for(int&i:h) cin >> i;
    string s;
    cin >> s;
    int m = 0;
    for(char c: s) {
         m = max(m, h[c-'a']);       
    }
    cout << (m*s.size()) << endl;
    return 0;
}