#include<bits/stdc++.h>
#define N 1000000007
#define pb push_back
#define sc scanf
#define pf printf
#define pii pair<int,int >
#define ll long long
using namespace std;

int main()
{
	int a[26];
	int i;
	for(i=0;i<26;i++)
	cin>>a[i];
	
	string str;
	cin>>str;
	int maxval=0;
	for(i=0;i<str.length();i++)
	{
		maxval=max(maxval,a[str[i]-97]);
	}
	cout<<maxval*str.length();
	return 0;
}