#include <iostream>
#include <vector>
#include <string>


using namespace std;

#define ll long long int

int main()
{
	vector<ll> vec;
	vec.resize(26);
	for(int i=0;i<26;i++)
	{
		cin>>vec[i];
	}
	string s;
	cin>>s;
	ll width=0,height=0;
	for(int i=0;i<s.length();i++)
	{
		if(vec[int(s[i])-97]>height)height=vec[int(s[i])-97];
		width++;
	}
	cout<<width*height<<endl;
}