#include<iostream>
#include<stdio.h>
#include<algorithm>

using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define pb push_back
#define mp make_pair
typedef long long ll;
int main()
{
    //int n;
	//scanf("%d",&n);
	int a[26];
	rep(i,0,26)
	{
		scanf("%d",&a[i]);
	}
	string s;
	cin>>s;
	int h=0;
	rep(i,0,(int)s.size())
	{
		h=max(h,a[s[i]-'a']);
	}
	
	printf("%d\n",(int)s.size()*h);
	
	return 0;
}