#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 arr[26];
    
    for(int i=0;i<26;i++){
        cin>>arr[i];
    }
    
    string s;
    cin>>s;
    int maxi=0;
    for(int i=0;i<s.length();i++){
        maxi=max(maxi, arr[ s[i]-'a' ] );
    }

    cout<< s.length()*maxi;


    return 0;
}