#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 */ 
    long long int a[26], i, ans;
    for(i=0;i<26;i++){
        cin>>a[i];
    }
    string s;
    cin>>s;
    ans=a[s[0]-97];
    for(i=1;i<s.length();i++){
        if(a[s[i]-97]>ans){
            ans=a[s[i]-97];
        }
    }
    cout<<ans*s.length()<<endl;
    return 0;
}