#include <iostream>
#include <vector>

typedef long long ll;

using namespace std;

vector <vector <vector <ll> > > dp;

int main(){
    int n, k;
    cin>>n>>k;
    if(k == 2){
        cout<<2;
        return 0;
    }

    dp.resize(n + 1, vector <vector <ll> > (k, vector <ll> (2)));

    dp[1][1][0] = 1;
    dp[1][1][1] = 1;

    for(int i = 2; i <= n; i++){
        for(int j = 1; j < k; j++){
            if(j == 1){
                for(int c = 1; c < k; c++){
                    dp[i][j][0] += dp[i - 1][c][1];
                    dp[i][j][1] += dp[i - 1][c][0];
                }
            }
            else{
                dp[i][j][0] += dp[i - 1][j - 1][0];
                dp[i][j][1] += dp[i - 1][j - 1][1];
            }
        }
    }
    ll ans = 0;
    for(int i = 1; i < k; i++){
        ans += dp[n][i][0];
        ans += dp[n][i][1];
    }
    cout<<ans<<"\n";

    return 0;
}