#include<iostream>
#include<algorithm>

using namespace std;

int main() {
int i,a[26],j,r=0;
string s;
for(i=0;i<26;i++)
cin>>a[i];
cin>>s;
for(j=0;j<s.length();j++){
r=max(r,a[s[j]-'a']);
}
int x=s.length();
cout<<x*r;

	// your code goes here
	return 0;
}