#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
using namespace std;


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