#include<iostream>  
#include<cstdio>
#include<cmath>  
#include<cstring>  
#include<algorithm>  
using namespace std; 
long long n,m,f[66][9];
int main()
{ 
    freopen("nucle.in","r",stdin);        
    freopen("nucle.out","w",stdout);      
	cin>>n>>m;
	if(n==1){
	    cout<<"2";
		return 0;
	}
	f[1][0]=1;f[1][1]=1;
	for(int i=2;i<=n;i++){
		long long up=0;
		for(int j=0;j<m;j++)up+=f[i-1][j];
		f[i][0]=up;
		for(int j=1;j<m;j++){
		    f[i][j]=f[i-1][j-1];
		}
	}
	long long sum=0;
	for(int i=0;i<m;i++)sum+=f[n][i];
	cout<<sum;
    return 0;  
}