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

int main(){
    int ar[27];
    for(int i = 0; i < 26; i++ ){
       scanf( "%d", ar + i );
    }
    int mx = 0;
    string s;
    cin >> s;
    for( char &c: s ) {
        c = tolower( c );
        mx = max( mx, ar[c-'a'] );
    }
    cout << mx*s.size() << "\n";
    return 0;
}