#include <fstream>

using namespace std;

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

int n,k,p;
int v[5002];

long long factorial(int n)
{
    if (n<=1) return 1;
    return n*factorial(n-1);
}

int main()
{
    fin >> n >> k;

    p=n;
    while (p>=k)
        p-=k-1;

    n--,p--;

    fout << factorial(n)/(factorial(p)*factorial(n-p));

    return 0;
}