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


int main() {
    int n=26;
    vector<int> v(n);
    for(int i=0;i<n;i++)
        cin>>v[i];
    string s;
    cin>>s;
    int nn=s.size();
    int mx=INT_MIN;
    for(int i=0;i<nn;i++)
        mx=max(v[s[i]-97],mx);
    cout<<mx*nn<<endl;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}