/*
 *  p.cpp
 *  Created on: Aug 21, 2016
 *  Author: Tarun Anand
 *  Copyright (c) 2016 Tarun Anand. All rights reserved.
 */
#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define all(v) v.begin(),v.end()
#define loop(i,a,b) for(i=a;i<b;i++)
#define revloop(i,a,b) for(i=a;i>=b;i--)
#define stloop(it,v) for(it=v.begin();it!=v.end();++it)
#define ii pair<ll,ll>
#define MP make_pair
#define pb push_back
#define ll long long int
#define fill(v,d) memset(v,d,sizeof(v))
int main()
{  std::ios::sync_with_stdio(false);
   cin.tie(0);
   cout.tie(0);
   ll A[26],i,max,a;
   loop(i,0,26)
   { cin>>a;
     A[i]=a;
   }
   string b;
   cin>>b;
   max=0;
   loop(i,0,(ll)b.length())
   {  a=A[(int)b.at(i)-97];
	  if(a>max)
		  max=a;
   }
   cout<<b.length()*max;
   return 0;
}