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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int a[30];
    for(int i = 0; i < 26; i++) {
        cin >> a[i];
    }
    string s;
    cin >> s;
    
    int mx = 0;
    for(int i = 0; i < s.size(); i++) {
        mx = max(mx, a[s[i] - 'a']);
    }
    cout << mx * s.size() << endl;
    return 0;
}