/*------------------------------------\
*	Hariom Singh					  *
*	SVNIT Surat						  *
*									  *
*------------------------------------*/

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

#define pi 3.141592654
#define fix cout << fixed << setprecision(10)

#define fore(i,a,b) for(i=a;i<=b;i++)
#define forl(i,a,b) for(i=a;i<b;i++)
#define si(d) scanf("%d",&d)
#define sll(d) scanf("%lld",&d)
#define pin(d) printf("%d\n",d)
#define pln(d) printf("%lld\n",d)
#define ll long long
#define ull unsigned long long
int mod=1e9+7;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(NULL);
		int a[27];
		for (int i=0;i<26;i++)
		cin >> a[i];
		string s;
		cin >> s;
		int l=s.length();
		int max=-1;
		for (int i=0;i<l;i++)
		{
			if (a[s[i]-'a']>max)
			max=a[s[i]-'a'];
		}
		int ans =l*max;
		cout << ans << endl;
	return 0;
}