3004

#include <iostream>
#include <fstream>
#include <unordered_map>

using namespace std;

typedef pair<int, int> pr;

struct pair_hash {
    template <typename T1, typename T2>
    size_t operator () (const pair<T1, T2>& p) const {
        auto h1 = hash<T1>{}(p.first);
        auto h2 = hash<T2>{}(p.second);
        return h1 ^ h2;
    }
};

unordered_map<pr, int, pair_hash> us;

int foo(int n, int k) {
    if (n == k && n > 0) return 1;
    else if (n > 0 && k == 1) return 1;
    else if (k > n) return 0;
    else {
        pr a = make_pair(n - 1, k - 1);
        pr b = make_pair(n - k, k);
        if (us.count(a) == 0) us[a] = foo(a.first, a.second);
        if (us.count(b) == 0) us[b] = foo(b.first, b.second);
        return us[a] + us[b];
    }
}

int main() {
    ifstream fin("input.txt");
    ofstream fout("output.txt");

    int n, k;
    fin >> n >> k;
    fout << foo(n, k);

    fin.close();
    fout.close();
    return 0;
}