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


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