#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main()
{
	ll a[27];
	for(ll i=0;i<26;i++)
	cin>>a[i];
	char s[1000000];
	ll max1=-1;
    cin>>s;
    ll l1=strlen(s);
    ll i;
    for(i=0;i<l1;i++)
    {
    	max1=max(max1,a[s[i]-'a']);
    }
    cout<<max1*l1<<endl;
}