#include <iostream>
using namespace std;
typedef long long ll;

int main()
{
    int n;
    cin >> n;
    ll b[4]{0};
    for(int i = 0; i < n; i++){
        int a;
        cin >> a;
        b[min(a, 3)]++;
    }
    ll ans = b[1] * (b[1] - 1) + b[1] * b[2] * 3 + b[2] * (b[2] - 1) / 2 + b[3] * (b[3] - 1) / 2 + b[3] * b[1] * 2 + b[3] * b[2];
    cout << ans << endl;
}