#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
Int dp[2][20][1<<20];
signed main(){
  Int n,k;
  cin>>n>>k;
  memset(dp,-1,sizeof(dp));
  function<Int(Int, Int, Int)> dfs=
    [&](Int f,Int p,Int b)->Int{
      Int &res=dp[f][p][b];
      if(~res) return res;
      if(b+1==(1<<n)) return f;
      res=0;
      for(Int i=0;i<n;i++){
	if((b>>i)&1) continue;
	Int nf=p>i,nb=b|(1<<i);
	if(nf&&f) continue;
	nf|=f;
	res+=dfs(nf,i,nb);
      }
      //cout<<f<<" "<<p<<" "<<b<<":"<<res<<endl;
      return res;
    };
  k--;
  cout<<dfs(0,k,1<<k)<<endl;
  return 0;
}