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