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

#define REP(i,n) for(int i=0;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<29
#define LINF LLONG_MAX/3
#define MP make_pair
#define PB push_back
#define EB emplace_back
#define ALL(v) (v).begin(),(v).end()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;

int main(){
    int N,K;
    cin>>N>>K;
    K--;

    int ans=0;
    for(int i=0;i<(1<<N);i++){
        vector<int> v1,v2;
        for(int j=0;j<N;j++){
            if(i & (1<<j)){
                v1.push_back(j);
            }else{
                v2.push_back(j);
            }
        }
        if(v1.size()==0 or v2.size()==0) continue;

        bool f=true;
        for(int j=0;j<v2.size();j++) if(v2[j]==K) f=false;
        if(!f) continue;

        sort(ALL(v1));
        sort(ALL(v2));
        if(v1[v1.size()-1] < v2[0]) continue;
        if(v1[0]!=K) continue;

//        cout << v1 << " " << v2 << endl;
        ans++;
    }

    cout << ans << endl;
}