#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 a[26];
    for(int i=0;i<26;i++){
        cin>>a[i];
    }
    string s;cin>>s;
    int max = 0;
    for(int i=0;i<s.length();i++){
        if(max<a[s[i]-'a'])max = a[s[i]-'a'];
    }
    cout<<max*s.length();
    return 0;
}