#include<iostream>
using namespace std;
int main(){
	int a[26],i,j,max=0,area;
	char b[10];
	for(i=0;i<26;i++)
		cin>>a[i];
	cin>>b;
	i=0;
	while(b[i]!='\0'){
		if(a[b[i]-97]>max)
			max=a[b[i]-97];
	i++;
	}
	area=max*i;
	cout<<area<<endl;
return 0;
}