#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 height[26],max=0;
    string word;
    for(int i=0;i<26;++i)
        {
        cin>>height[i];
    }
    cin>>word;
    max = height[word[0] - 'a'];
    for(int i=1;i<word.length();++i)
        {
        if(height[word[i] - 'a'] > max)
            max = height[word[i] - 'a'];
    }
    cout<<max*word.length();
    return 0;
}