#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(int argc, char* argv[])
{
	int N,K,i;
	cin>>N>>K;
	vector<int> V(N);
	for (i=0;i<N;i++){
		V[i]=i+1;
	}
	int ans=0;
	do{
		if (V[0]==K){
			int num=0;
			for (i=0;i<N-1;i++){
				if (V[i]>V[i+1]){
					num++;
					if (num>=2){
						break;
					}
				}
			}
			if (num==1){
				ans++;
			}
		}
	}while(next_permutation(V.begin(),V.end()));
	cout<<ans<<endl;
	return 0;
}