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

typedef long long LL;

#define PII       pair<int,int>
#define all(c)    c.begin(),c.end()
#define sz(c)     (int)c.size()
#define clr(c)    c.clear()
#define pb        push_back
#define mp        make_pair
#define cin(x)    scanf("%d",&x)
#define MOD		1000000007
#define EPS		1E-10

int main()
{
	int abc[30] = {0};
	for(int i = 0; i < 26; i++)
		cin >> abc[i];
	string s;
	cin >> s;
	int maxH = 0;
	LL wid = sz(s);
	for(int i = 0; i < sz(s); i++)
		maxH = max(maxH, abc[s[i] - 'a']);
	cout << maxH * wid << "\n";
	return 0;
}