#include<bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
	ll a[26];
	for(int i=0;i<26;i++) {
		cin>>a[i];
	}
	string s;
	cin>>s;
	ll n = s.size();
	ll maxx = 0;
	for(int i=0;i<n;i++) {
		maxx = max(maxx, a[s[i] - 'a']);
	}
	cout<<n*maxx<<"\n";
	return 0;
}