#include <fstream>
#include <iomanip>
#include <algorithm>
#include <numeric>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <utility>
#include <cmath>
#include <functional>
#include <stack>
#include <set>
#include <iostream>

using namespace std;

int main()
{
	int h[26];
	for (int i = 0; i < 26; ++i) 
		cin >> h[i];
	string s;
	cin >> s;
	int maxh = 0;
	for (int i = 0; i < s.size(); ++i)
		maxh = max(maxh, h[s[i]-'a']);
	cout << maxh * s.size() << endl;
	return 0;
}