#include<bits/stdc++.h>
using namespace std;
constexpr int Inf = 2000000000;
constexpr long long INF= 2000000000000000000;

template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }

template<typename T,typename U>
T modpow(T N, U P, T M = -1) {
    if(P < 0) return 0;
    T ret = 1;
    if(M != -1) ret %= M;
    while(P) {
        if(P & 1) {
            if(M == -1) ret *= N;
            else ret = ret * N % M;
        }
        P /= 2;
        if(M == -1) N *= N;
        else N = N * N % M;
    }
    return ret;
}

constexpr long long MOD = 998244353;

int main() {
    int n;
    cin >> n;
    map<int,int> ma;
    for(int i = 0;i < n;i++) {
        int a;
        cin >> a;
        ma[a]++;
    }

    auto fac = [&](int a) -> long long {
        long long res = 1;
        for(long long i = 1;i <= a;i++) res *= i;
        return res;
    };

    long long ret = fac(n);
    for(auto& [key,value]: ma) {
        ret /= fac(value);
    }

    cout << ret << endl;
}