#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <bitset>
#include <set>
#include <deque>
#include <stack>
#include <atcoder/all>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < (t); ++i)
#define dsrep(i,t,s) for(int i = (t)-1; i >= (s); --i)
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
int dx4[4]={1,0,-1,0};
int dy4[4]={0,-1,0,1};
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using P = pair<int,int>;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
const ll mod = 998244353;

////////////////////////////////////////////
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll n;
  cin >> n;
  vector<ll> a(n);
  ll one = 0, two = 0;
  rep(i, n) {
    cin >> a[i];
    if(a[i] == 1) one++;
    if(a[i] == 2) two++;
  }

  ll ans = 0;
  ans += (one * two) * 3;
  ans += (one * (n - two - one)) * 2;
  if(one > 0) ans += ((one) * (one - 1) / 2) * 2;
  if(n != one) ans += (n - one) * (n - one - 1) / 2;

  cout << ans << endl;
}