#define _CRT_SECURE_NO_WARNINGS
#include<sstream>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<random>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())


int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int h[26];
	rep(i, 26)cin >> h[i];
	string s;
	cin >> s;
	int m = 0;
	rep(i, s.size())m = max(m, h[s[i] - 'a']);
	cout << m*s.size() << endl;

	return 0;
}