/* -*- coding: utf-8 -*-
 *
 * 1470.cc:  No.1470 Mex Sum - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

int cs[4];

/* subroutines */

inline ll nc2(int n) { return (ll)n * (n - 1) / 2; }

/* main */

int main() {
  int n;
  scanf("%d", &n);

  for (int i = 0; i < n; i++) {
    int ai;
    scanf("%d", &ai);
    cs[min(3, ai)]++;
  }

  ll sum =
    nc2(cs[1]) * 2 + (ll)cs[1] * cs[2] * 3 + (ll)cs[1] * cs[3] * 2 +
    nc2(cs[2]) + (ll)cs[2] * cs[3] + nc2(cs[3]);

  printf("%lld\n", sum);
  return 0;
}