#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define min3(a,b,c) min(min((a),(b)),(c))
int main() {
	ios_base::sync_with_stdio(0);
	int h[26];
	for (int i = 0; i < 26; i++) {
		cin >> h[i];
	}
	string s;
	cin >> s;
	int mh = 0;
	for (auto i : s) {
		mh = max(mh, h[i - 'a']);
	}
	cout << mh * s.length() << endl;
	return 0;
}