#include <bits/stdc++.h>

using namespace std;
typedef long long ll;


int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	ll ones = 0, twos = 0, rest = 0, result = 0;
	ll sizer;
	cin >> sizer;

	for(int i = 0; i < sizer; i++)
	{
		ll value;
		cin >> value;
		if(value == 1) ones++;
		else if(value == 2) twos++;
		else rest++;		
	}

	result += rest * (rest - 1) / 2;
	result += 2 * (ones * rest);
	result += (ones * (ones - 1));
	result += 3 * (twos * ones);

	cout << result << endl;

}