#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 h[26];
    for(int i = 0 ; i < 26;i++) cin >> h[i];
    string s;
    cin >> s;
    int ans = 0;
    int w = 0, hg = 0;
    for(int i = 0 ; i < s.length();i++)
      hg = max(hg,h[s[i] - 'a']);
    cout << hg * (int)s.length() << "\n";
    return 0;
}