#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++)
#define rip(i,a,b) for(int i=(int)a;i>=(int)b;i--)
#define ll long long
#define MOD 1000000007
#define N 200005
#define f first
#define s second
#define pii pair<int,int>
#define PI acos(-1)
#define INF 1000000
int a[N];
int main()
{
    ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	rep(i,0,25)
	cin>>a[i];
	string s;
	cin>>s;
	int l=s.length(),ans=0;
	rep(i,0,l-1)
	{
	    ans=max(ans,a[s[i]-'a']);
	}
	cout<<ans*l<<endl;
    return 0;
}