// Sandokan
#include <fstream.h>

ifstream fin("sandokan.in");
ofstream fout("sandokan.out");



int main(){
	int A[2][5100],i,j,n,k,c;
      fin>>n>>k;
      c=n%(k-1);
      if (c==0) c=k-1;

      for (i=1;i<=2;i++)
         	A[0][i]=0;
      A[1][0]=1;
      A[0][0]=1;
      for (i=1;i<=n-1;i++){
         	for (j=1;j<=i;j++)
               	A[i%2][j]=A[(i+1)%2][j]+A[(i+1)%2][j-1];
            A[i%2][i+1]=0;
      }
	fout<<A[(n-1)%2][k-1];
      fout.close();


}