#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define maxn 500002
#define mmaxn 1000000000
#define pii pair<int,int>
#define pll pair<ll int,ll int>
#define pdd pair<double,double>
#define mp make_pair
using namespace std;
int main(){
	map<char,int> x ;
	int temp;
	for(int i=0;i<26;i++){
		cin>>temp;
		x['a'+i]=temp;
	}	
	string a;
	cin>>a;
	int m=-1;
	for(int i=0;i<a.size();i++){
		m=max(x[a[i]],m);
	}
	cout<<m*a.size()<<"\n";
}