import java.util.Scanner;
public class Probability {
    public static double factorial(double num){
        int fact=1;
        for(int i=2;i<=num;i++){
            fact*=i;
        }
        return fact;
    }
    public static int probability(int n,int x){
        double Ns,Ne1,Ne2;
        int Pe;
        Ns=factorial(8.0)/(factorial(n*1.0)*factorial(8.0-n));
        Ne1=factorial(4.0)/(factorial(x*1.0)*factorial(4.0-x));
        Ne2=factorial(4.0)/(factorial(((n-x)*1.0))*factorial((4.0-(n-x))));
        Pe=(int)(((Ne1*Ne2)/Ns)*100);
        return Pe;
    }
    public static void main(String[] args){
        try (Scanner s = new Scanner(System.in)) {
            int n = s.nextInt();
            int x = s.nextInt();
            int result = probability(n, x);
            System.out.println(result);
        }
    } 
}