#include <stdio.h>
#include <stdlib.h>
int n,k; //n阶，一次最多k阶
int member[100000]={0};
int  f(int x)//
{
    if(member[x]!=0) return member[x];
    int ans=0;
    if(x==0) return member[x]=1;
    if(x<=k) {
               for(int t=0;t<x;t++)
                  ans+=f(t);
                 return member[x]=ans;
             }
    if(x>k){
              for(int t=x-1;t>=x-k;t--)
                  ans+=f(t);
              return member[x]=ans;
             }
}
int main()
{
    scanf("%d%d",&n,&k);
    printf("%d",f(n));

}