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


int main() {
    int n = 26;
    string s;
    int a[n];
    for(int i=0;i<n;i++)
        cin >> a[i];
    cin >> s;
    //cout << s << endl;
    int mx = 0;
    for(int i=0;s[i];i++) {
        mx = max(mx,a[s[i]-'a']);
    }
    cout << mx * s.length() << endl;
    return 0;
}