#include <bits/stdc++.h>

using namespace std;

#define mid (lf + rg >> 1)
#define right (left | 1)
#define left (v << 1)

#define pb push_back
#define mp make_pair
#define nd second
#define st first

typedef long long ll;
typedef pair < int, int > pii;

const ll linf = 1e18 + 9;
const int inf = 1e9 + 9;
const ll mod = 1e9 + 7;
const int N = 5e5 + 9;

int a[N];
string str;

int main() {

	for (int i = 1; i <= 26; i++) scanf("%d", &a[i]);

	cin >> str;

	int res = 0;
	for (int i = 0; i < str.size(); i++) if (a[str[i] - 'a' + 1] > res) res = a[str[i] - 'a' + 1];

	cout << res * str.size() << endl;

	return 0;
}