#include <bits/stdc++.h>
#include <atcoder/all>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=b-1;i>=a;i--)
#define all(x) (x).begin(),(x).end()
#define pb(x) push_back(x);
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
typedef long long ll;
typedef long double lld;
using namespace std;
using namespace atcoder;
using mint=static_modint<1000000007>;
const ll mod=998244353;
//const ll mod=1e9+7;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
const string zton="0123456789";
const string atoz="abcdefghijklmnopqrstuvwxyz";
const ll inf=(1ll<<60);
ll gcd(ll a,ll b){
    ll r;
    r=a%b;
    if(r==0){
        return b;
    }
    else{
        return gcd(b,r);
    }
}
typedef pair<ll,int> P;

int main(void){
    int N;cin >> N;
    int A[N];rep(i,0,N)cin >> A[i];
    sort(A,A+N);
    int pre=0;
    int cnt=1;
    ll ans=1;
    rep(i,0,N){
        ans*=(i+1);
        if(A[i]!=pre){
            pre=A[i];
            cnt=1;
        }
        else{
            cnt++;
        }
        ans/=cnt;
    }
    cout << ans << endl;
}