#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 */   
    vector<int> size(26, 0);
    for(int i = 0; i < 26; i++){
        cin>>size[i];
    }
    string s;
    cin>>s;
    int maxs = 0;
    for(int i = 0; i < s.size(); i++){
        if(size[s[i] - 'a'] > maxs)
            maxs = size[s[i] - 'a']; 
    }
    cout<<s.size() * maxs<<endl;
    return 0;
}