DAYCON.CPP

#include <bits/stdc++.h>
using namespace std;

#define taskname "DAYCON"

const int N = 25;

int n, m, cnt = 0;
int a[N], dp[N][N];

void print() {
  ++cnt;
  /*cout << cnt << ": ";
  for (int i = 1; i <= n; i++) {
    cout << a[i];
  }
  cout << '\n';*/
}

void brute(int i) {
  for (int j = 1; j <= m; j++) {
    // kiem tra
    bool flag = false;
    for (int k = i - 1; k >= 1; k--) {
      if (a[k] == j) {
        int t = dp[k - 1][i - 1] + 1;
        if (t >= i - k) {
          flag = true;
          break;
        }
      }
    }
    if (flag) continue;

    // them
    for (int k = i - 1; k >= 1; k--) {
      if (a[k] == j) {
        int t = dp[k - 1][i - 1] + 1;
        dp[k][i] = t;
      }
    }
    a[i] = j;

    if (i == n) print();
    else brute(i + 1);

    // xoa
    for (int k = i - 1; k >= 1; k--) {
      if (a[k] == j) {
        dp[k][i] = 0;
      }
    }
    a[i] = 0;
  }
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  if (fopen(taskname".INP", "r")) {
    freopen(taskname".INP", "r", stdin);
    freopen(taskname".OUT", "w", stdout);
  }
  cin >> n >> m;
  brute(1);
  cout << cnt << '\n';
}