#include <bits/stdc++.h>

using namespace std;
#define LL long long
#define rep(i,a,b) for(LL i = a; i<=b ; ++i)

LL arr[30];

LL n;


int main()
{
    rep(i , 0, 25)cin >> arr[i];

    string s;
    cin >> s;LL maxi = 0;
    rep( i , 0 , s.size()-1)
    {
        maxi = max(maxi , arr[s[i]-'a']);
    }

    cout << maxi*s.size();


    return 0;
}