/*      my general mistakes that costed me a lot
          * check for overflows
          * check and mod and use int type variables where possible to avoid tles
          * while multiplying two variables whose value can exceed integer 
          limt make sure to typecase them
          * use scanf when you are not working with the best possible optimisation
          * return a value from a function that has a return type sometimes the 
          compiler may give the correct answer but there will be problem in the judge
          * be very cautious about uninitiaalised variables , infact never keep them
          or handle them properly
		  *never use inbuilt log function or pow function it fucking ruins everything
		  */
#include<bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define mp make_pair
#define pb push_back
#define ll long long int
#define pp pair<int,int> 
#define ve vector
#define mod 1000000007
#define mn 100010
int dx[]={-1,-1,+0,+1,1,+1,+0,-1}; // anticlockwise starting from up!
int dy[]={+0,-1,-1,-1,0,+1,+1,+1};
/************************************CODE BEGINS HERE************************/
int main()
{
	    string s;
	    int a[30];
	    memset(a,0,sizeof(a));
	    for(int i=0;i<26;i++)
	    {
	    	  cin>>a[i];
		}
		cin>>s;
		int mx=0;
		int l=s.length();
		for(int i=0;i<l;i++)
		{
			   mx=max(mx,a[s[i]-'a']);
		}
		cout<<l*mx<<endl;
		return 0;
}