#include <fstream>
using namespace std;
unsigned long long v[10001],n,k,i,y;
int main()
{
    ifstream f1("recurenta.in");
    ofstream f2("recurenta.out");
    f1>>n>>k;
    for (;i<k;++i)
        v[i]=1;
    while (i<=n)
    {
        for (y=1;y<=k;++y)
            v[i]+=v[i-y];
        ++i;
    }
    f2<<v[n]<<'\n';
    f1.close();
    f2.close();
    return 0;
}