#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long int
#define INF INT_MAX
#define mod 1000000007
int main()
{
	int a[26];
	for(int i=0;i<26;i++)
	{
		cin>>a[i];
	}
	string s;
	cin>>s;
	int h=0;
	for(int i=0;i<s.length();i++)
	{
		if(a[s[i]-97]>h)
			h=a[s[i]-97];
	}
	cout<<h*s.length()<<endl;
}