#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int, int>;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; --i)

int main() {
    int n;
    cin >> n;
    map<int, int> mp;
    rep(i, n) {
        int a;
        cin >> a;
        mp[a]++;
    }
    vector<ll> fac(n + 1);
    fac[0] = 1;
    rep(i, n) fac[i + 1] = fac[i] * (i + 1);
    ll ret = fac[n];
    for (auto [_, k] : mp) ret /= fac[k];
    cout << ret << endl;
    return 0;
}