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

int main() {
	int n, MOD = 1e9;
	cin >> n;
	vector<int> v(n);
	for(int i = 0; i < n; i++) cin >> v[i];

	sort(v.begin(), v.end());
	v.push_back(-1);

	unsigned long long p = 1;
	int c = 1;
	bool elso = true;
	for(int i = 1; i <= n; i++) {
		if(v[i] == v[i-1]) c++;
		else {
			if(!elso) p = p*(c+1) % MOD;
			else elso = false;
			c = 1;
		}
	}
	cout << p;

	return 0;
}