#include <bits/stdc++.h>
using namespace std;
#define ll long long 
#define _ ios::sync_with_stdio(false);
#define mem(x,a) memset(x,(a),(int)(sizeof(x)))
#define pii pair<int,int>
#define fr(i,a,n) for(int i=(a);i<=(n);i++)
#define frd(i,a,n) for(int i=(a);i>=(n);i--)
#define bitcount __builtin_popcount
#define ison(a,b) (a&(1<<b))
#define s(n) scanf("%d",&(n)) 
#define sl(n) scanf("%lld",&(n))
#define nl cout<<endl
#define pb push_back
#define mp make_pair 
#define F first 
#define S second
#define V vector
ll mod=1e9+7;
int h[110];
int main() {
	fr(i,0,25)cin>>h[i];
	string s;
	cin>>s;
	int n=s.length();
	int maxh=0;
	fr(i,0,n-1)
	{
		maxh=max(maxh,h[s[i]-'a']);
	}
	//cout<<maxh<<endl;
	int
	 ans=maxh*n;
	cout<<ans<<endl;
	return 0;
}