#include<bits/stdc++.h>
using namespace std;
#define mk make_pair
#define pb push_back
#define ll long long int
#define lf double
#define M 1000000007
int main()
{       int i,maxi=0,a[30];
string s;
        for(i=0;i<26;i++)
        cin>>a[i];
        cin>>s;
        for(i=0;i<s.size();i++)
        maxi=max(maxi,a[s[i]-'a']);
        cout<<maxi*(int)(s.size())<<endl;
}