#include <bits/stdc++.h>

std::map<std::pair<int, int>, int> cache;
int junior5(int n, int k) {
    if(n < k) {
        return 0;
    }
    if(k == 1 || k == n) {
        return 1;
    }
    if(cache.find(std::pair<int, int>(n, k)) != cache.end()) {
        return cache[std::pair<int, int>(n, k)];
    }
    cache[std::pair<int, int>(n, k)] = junior5(n - 1, k - 1) + junior5(n - k, k);
    return cache[std::pair<int, int>(n, k)];
}

int main() {
    int a, b;
    std::cin >> a >> b;
    std::cout << junior5(a, b) << std::endl;
    return 0;
}