#include <cmath>
#include <string>
#include <cstdio>
#include <iostream>

using namespace std;


int main(){
	int h[30];
    for(int h_i = 0; h_i < 26; h_i++){
       cin >> h[h_i];
    }
    string word;
    cin >> word;
    
    int hm = 0;

    for (int i = 0; i < word.length(); i++) {
    	hm = max(hm, h[word[i] - 'a']);
    }

    cout << word.length() * hm << endl;
    
    return 0;
}