#include "bits/stdc++.h"
using namespace std;

//諸機能
#pragma region MACRO 
#define putans(x)  std::cerr << "answer: " ; cout << (x) << endl
#define dputans(x) std::cerr << "answer: "; cout << setprecision(10) << (double)(x) << endl
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define RREP(i,a,n) for(int i=(int)(n-1); i>= a; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) begin((a)),end((a))
#define mp make_pair
#define exist(container, n) ((container).find((n)) != (container).end())
#define substr(s,i,l) string((s), (i), (l))
#define tos(x) (to_string((x)))
#ifdef _DEBUG //ファイルからテストデータを読み込む
std::ifstream ifs("data.txt");
#define put ifs >>
#else //いい感じにやる
#define put cin >>
#endif
#pragma endregion
//デバッグなどの支援
#pragma region CODING_SUPPORT
#define dbg(var0) { std::cerr << ( #var0 ) << "=" << ( var0 ) << endl; }
#define dbg2(var0, var1) { std::cerr << ( #var0 ) << "=" << ( var0 ) << ", "; dbg(var1); }
#define dbg3(var0, var1, var2) { std::cerr << ( #var0 ) << "=" << ( var0 ) << ", "; dbg2(var1, var2); }
#define dbgArray(a,n) {std::cerr << (#a) << "=";  rep(i,n){std::cerr <<(a[i])<<",";} cerr<<endl;} 
#ifndef _DEBUG
#define dbg1 {}
#define dbg2 {}
#define dbg3 {}
#define dbgArray {}
#endif 
#pragma endregion 
//typedef（書き換える、書き足す可能性ある）
#pragma region TYPE_DEF
typedef long long ll;
typedef pair<int, int> pii; typedef pair<string, string> pss; typedef pair<int, string>pis;
typedef vector<string> vs; typedef vector<int> vi;
#pragma endregion
//諸々の定数(書き換える可能性ある)
#pragma region CONST_VAL
#define PI (2*acos(0.0))
#define EPS (1e-9)
#define MOD (ll)(1e9 + 7)
#define INF (ll)(1e9)
#pragma endregion

bool used[20];
int N;
int K;

int f(bool sorted,int last,int count) {
	dbgArray(used, 5);
	int ans = 0;
	if (count == N) {
		dbgArray(used,5);
		dbg("ok");
		return 1;
	}
	if (sorted) {
		if (( last == 0 )) {
			dbg("ng");
			return 0;
		}
		else {
			RREP(i,0,last) {
				if (!used[i]) {
					used[i] = true;
					ans += f(true, i, count + 1);
					used[i] = false;
					break;
				}
			}
		}
	}
	else {
		REP(i,0,last){
			used[i] = true;
			ans += f(false, i, count + 1);
			used[i] = false;
		}
		ans += 1;
	}
	return ans;
}


int main() {
	int n, k; put n >> k;
	N = n; K = k-1;
	//used[k-1] = true;
	if (n = 2) {
		putans(0);
		goto END;
	}
	putans(1<<(k-1));
END:

	return 0;
}