#include<bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define pb push_back
#define mp make_pair
#define var(X) cerr << " --> " << #X << " = " << X << endl
#define arr(a,n) for(int i=0;i<n;i++){if(i==0) cout<<"Results for array "<< #a <<"\n";cout<<a[i]<<" ";} cout<<endl
#define arr1(a,n) for(int i=1;i<=n;i++){if(i==1) cout<<"Results for array "<< #a <<"\n";cout<<a[i]<<" ";} cout<<endl


typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<pair<int,int> > vii;
const double eps = 1e-10, pi = acos(-1.0);

int h[30];

int main()
{
	/*
	#ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("out.txt","w",stdout);
	#endif
	*/
	
	int t=1;
	//scanf("%d",&t);
	while(t--)
	{
		int n,x=0,y;
		for(int i=0;i<26;i++)
		cin>>h[i];
		string str;
		cin>>str;
		for(int i=0;i<str.size();i++)
		x=max(x,h[str[i]-'a']);
		cout<<(x*str.size());
	}
	return 0;
}