#include <fstream>

using namespace std;

int n,k,x,i,a[2][5001],p,j,t;

ifstream fin ("sandokan.in");

ofstream fout ("sandokan.out");

int main (){

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

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

    fout<<a[1-t][p-1];


    return 0;
}