#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
#include<string>

using namespace std;


int main(){
	vector<int> letters(26);
	for (int i = 0; i < 26; i++){
		scanf("%d", &letters[i]);
	}
	string str;
	cin >> str;
	int maxht = 0;
	for (int i = 0; i < str.length(); i++){
		if (letters[(int(str[i]) - 97)] > maxht)
			maxht = letters[(int(str[i]) - 97)];
	}
	printf("%d", maxht*str.length());
}