#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){

    ll N, ans=0, A, a=0, b=0;
    cin >> N;
    for (int i=0; i<N; i++){
        cin >> A;
        if (A == 1) a++;
        else if (A == 2) b++;
    }

    ans += (a*(a-1)/2+a*(N-a-b))*2;
    ans += a*b*3;
    ans += (N*(N-1)/2-a*(a-1)/2+a*(N-a-b)-a*b);

    cout << ans << endl;

    return 0;
}