//Author Ruchir		
#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define ll  long long int
#define pi pair<ll,ll>
#define pii pair<ll,pi>
#define f first
#define mp make_pair
#define s second
#define pb push_back
int a[29];int maxx=0;
int main(){
	rep(i,26)cin>>a[i];
	string s ;cin>>s;
	int len=s.size();
	rep(i,len){
       int x=s[i]-'a';
		maxx=max(maxx,a[x]);}

		cout<<maxx*len;
}