#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int fv [ 28 ] ;
    memset ( fv , 0 , sizeof ( fv ) ) ;
    for ( int i = 0 ; i <= 25 ; ++ i ) {
        cin >> fv [ i ] ; 
    }
    char sir [ 155 ] ;
    cin >> ( sir + 1 ) ; 
    int l = strlen ( sir + 1 ) ; 
    int maxim = 0 ; 
    for ( int i = 1 ; i <= l ; ++ i ) {
        maxim = max ( maxim , fv [ sir [ i ] - 'a' ] ) ;
    }
    cout << maxim * l ;
    return 0;
}