using System.Linq;
using System.Collections.Generic;
using System;

public static class combi
{
    public static IEnumerable<IEnumerable<T>> Comb<T>(this IEnumerable<T> items, int r)
    {
        if (r == 0)
        {
            yield return Enumerable.Empty<T>();
        }
        else
        {
            var i = 1;
            foreach (var x in items)
            {
                var xs = items.Skip(i);
                foreach (var c in Comb(xs, r - 1))
                    yield return c.Before(x);
                i++;
            }
        }
    }
    public static IEnumerable<T> Before<T>(this IEnumerable<T> items, T first)
    {
        yield return first;
        foreach (var i in items)
            yield return i;
    }
}

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var k = int.Parse(line[1]);
        getAns(n, k);
    }
    static void getAns(int n, int k)
    {
        var a = Enumerable.Range(1, n).ToList();
        a.Remove(k);
        var count = 0;
        for (int i = 0; i < n - 1; i++)
        {
            var a0 = new List<int>();
            var w = a.Comb(i);
            foreach (var x in w)
            {
                a0.Clear();
                a0.Add(k);
                var used = new bool[n + 1];
                used[k] = true;
                foreach (var y in x)
                {
                    a0.Add(y);
                    used[y] = true;
                }
                var minb = 0;
                for (int j = 1; j <= n; j++)
                {
                    if (!used[j]) { minb = j; break; }
                }
                a0.Sort();
                if (a0[0] == k && a0[i] > minb) count++;
            }
        }
        Console.WriteLine(count);
    }
}