#include <iostream>
#include <cmath>
#include <math.h>
#include <vector>
#include <set>
#include <unordered_set>
#include <tuple>
#include <map>
#include <unordered_map>
#include <string>
#include <string.h>
#include <utility>
#include <algorithm>
#include <queue>
#include <deque>
#include <iterator>
#include <stdlib.h>
#include <cstdlib>
#include <bitset>
#include <fstream>
#include <iomanip>
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC optimize("fast-math")
// #pragma GCC optimize("vpt")
// #pragma GCC optimize("rename-registers")
// #pragma GCC optimize("move-loop-invariants")
// #pragma GCC optimize("unswitch-loops")
// #pragma GCC optimize("branch-target-load-optimize")
// #pragma GCC optimize("branch-target-load-optimize2")
// #pragma GCC optimize("btr-bb-exclusive")

typedef long long ll;
typedef long double ld;
#define all(x) x.begin(), x.end()

using namespace std;

int main() {
    int n = 0, k = 0; cin >> n >> k;
    vector<vector<ll>> dp(k + 2, vector<ll> (n + 2, 0));
    for (int i = 1; i <= n; ++i) {
        dp[1][i] = 1;
    }
    for (int i = 2; i <= k; ++i) {
        for (int j = 2; j <= n; ++j) {
            for (int q = 0; q <= j - 2; ++q) {
                dp[i][j] += dp[i - 1][q] * (j - q - 1);
            }
        }
    }
    cout << dp[k][n];
}