//Giorgi Kldiashvili

#include <bits/stdc++.h>

#define fr first
#define sc second
#define INF 2e7
#define M (int)1e9

using namespace std;

string a;
int A[26];
int s;

int main()
{
	for(int i = 0; i < 26; ++ i)
		cin >> A[i];
	cin >> a;

	for(int i = 0; i < a.length(); ++ i)
		s = max(s, A[a[i] - 'a']);
	s *= a.length();

	cout << s;
}