/*
    
    Jaydeep Khandelwal,
    CSE 2nd year,
    MNNIT Allahabad
    
    Kathumar, Alwar, Rajsthan.
    
*/

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

//Constants:
#define mod 1000000007
#define INF 1000000000
#define INFL 1000000000000000000
#define N 100005
#define PI 3.14

//Shortcuts:
#define ll long long
#define vec vector<ll>
#define matrix vector<vector<ll> >
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define sn struct node
#define sf1(a) scanf("%lld",&a);
#define sf2(a,b) scanf("%lld%lld",&a,&b);
#define sf3(a,b,c) scanf("%lld%lld%lld",&a,&b,&c);
#define pf1(a) printf("%lld\n",a);
#define pf2(a,b) printf("%lld %lld\n",a,b);
#define pf3(a,b,c) printf("%lld %lld %lld\n",a,b,c);
#define ffor(a,b) for(i=a;i<=b;i++)
#define rfor(a,b) for(i=a;i>=b;i--)

//Mistakes:
#define pritnf printf


int main()
{
	ll a[N],t,i=0,j,k,x,y,z,count=0,p,flag=0,ans=0,sum=0,l,n,m,max1=0,min1,pos,tmp,c[300];
	
	string s;
	
	for(i=0;i<26;i++)
	{
	    scanf("%lld",&c[i]);
	    
	}
	
	cin >> s;
	
	l=s.length();
	
	for(i=0;i<l;i++)
	{
	    
	    max1=max(max1,c[s[i]-'a']);
	    
	    
	    
	    
	    
	}
	
	ans=l*max1;
	
	printf("%lld\n",ans);
	
	
	return 0;
}