#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define ff first
#define ss second
#define pb push_back
#define mp make_pair

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

void solve() {

	vector<int> sz(26);
	for(int i = 0; i < 26; i++) cin >> sz[i];
	
	string s;
	cin >> s;

	int max_h = 0;

	for(char c : s){
		max_h = max(max_h, sz[c - 'a']);
	}

	int ans = max_h * s.size();
	cout << ans;

	
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef LOCAL
		ifstream in("in");
		cin.rdbuf(in.rdbuf());
	#endif

	solve();

	return 0;
}