//package algorithm;


import java.util.Scanner;

public class PDFViewer {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		int arr[]=new int[26];
		for(int i=0;i<26;i++){
			arr[i]=s.nextInt();
			//System.out.println(arr[i]+" inserted.");
		}
		s.nextLine();
		String word = s.next();
		s.close();
		
		//System.out.println(word);
		
		int result=1;
		
		//System.out.println(word.length());
		for(int i=0;i<word.length();i++){
			int num = Math.abs(97 - (int)(word.charAt(i)));
			//System.out.println(num);
			//System.out.println(arr[num]);
			result *= arr[num];  
		}
		
		int finalResult= result * word.length();
		
		System.out.println(finalResult);

	}

}