#include <fstream>

using namespace std;

int n,k,v[5001],i,a[5001][5001],p,j;

ifstream fin ("sandokan.in");

ofstream fout ("sandokan.out");

int main (){

    fin>>n>>k;
    for (i=1;i<=n;i++)
        fin>>v[i];
    p = n%(k-1);
    // combinari de n luate cate p-1

    for (i=0;i<=n;i++)
        for (j=0;j<=i;j++){
            if (j == 0)
                a[i][j] = 1;
            else
                a[i][j] = a[i-1][j-1] + a[i-1][j];
        }
    fout<<a[n][p-1];


    return 0;
}