import java.util.Scanner;

public class A {
    public static void main(String[] args) {
                Scanner in = new Scanner(System.in);    
            int n = in.nextInt();
           int m = in.nextInt();
        System.out.println(sum(n, m));
    }     
    static int sum(int n, int m) {
        if (m < 0)
            return 0;
        if (m == 0)
            return 1;
        if (m > 0 && n <= 0)
            return 0;
        int sum = 0;
        for (int i = 1; i <= n; i++) {
            sum += sum(i - 1, m - i);
        }
        return sum;
    }
}