#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;

using ll = long long;
const int INF = 1e9;
const ll inf = 1LL<<62;

void solve() {
  auto f = [](__int128_t x) -> __int128_t {
    __int128_t res = 1;
    for (__int128_t i=2; i<=x; i++) res *= i;
    return res;
  };
  int n; cin >> n;
  map<int, int> m;
  for (int i=0; i<n; i++) {
    int a; cin >> a;
    m[a]++;
  }
  __int128_t ans = f(n);
  for (auto p : m) ans /= f(p.second);
  cout << (ll)(ans) << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  // int t; cin >> t;
  /*while (t--)*/ solve();
}