/*NAME: SANYAM GARG
INSTITUTION:DELHI TECHNOLOGICAL UNIVERSITY*/
#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<bits/stdc++.h>
#include<stack>
#include<queue>
#include<list>
#include<vector>
#include<bitset>
#define mod 1000000007
#define li long long int
#define ll int
#define readi(x) scanf("%d",&x)
#define  reads(x)  scanf("%s",&x)
#define readl(x) scanf("%I64d",&x)
#define rep(i,n) for(i=0;i<n;i++)
#define revp(i,n) for(i=(n-1);i>=0;i--)
#define myrep1(i,a,b) for(i=a;i<=b;i++)
#define myrep2(i,a,b) for(i=b;i>=a;i--)
#define pb push_back
#define mp make_pair
#define fi first
#define sec second
#define MAXN 2000000000000000000
using namespace std;
int main()
{
	li  i,ans;
	char c[20];
	li ar[30];
rep(i,26)
{
	cin>>ar[i];
}
ans=0;
reads(c);
for(i=0;c[i]!='\0';i++)
{
	ans=max(ans,ar[c[i]-'a']);
//	cout<<ans<<endl;
}
cout<<ans*strlen(c);
}