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

int h[27];

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    for(int i = 0; i < 26; i++)
        cin >> h[i];
    string s; cin >> s;
    int len = s.length();
    int maxht =-1;
    for(int i = 0; i < len; i++)
        {
        maxht = max(maxht,h[s[i]-'a']);
    }
    cout << maxht*len;
    return 0;
}