#include #include using namespace atcoder; #define rep(i, n) for(ll i = 0; i < n; i++) #define rep2(i, m, n) for(ll i = m; i <= n; i++) #define rrep(i, m, n) for(ll i = m; i >= n; i--) #define all(a) a.begin(), a.end() #define rall(a) a.rbegin(), a.rend() #define MAX(x) *max_element(all(x)) #define MIN(x) *min_element(all(x)) #define SZ(a) ((ll)(a).size()) using namespace std; typedef long long ll; typedef pair P; const ll mod = 1000000007; const int dx[4] = { -1, 1, 0, 0 }; const int dy[4] = { 0, 0, 1, -1 }; const int inf = 1e9 + 1; const ll INF = 1e18 + 1; const double pi = acos(-1); using Graph = vector>; Graph G; typedef atcoder::modint1000000007 mint; //typedef atcoder::modint998244353 mint; //typedef modint mint; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); ll n; cin >> n; vector sc(3, 0); rep(i, n) { int a; cin >> a; a--; a = min(a, 2); sc[a]++; } ll m = n * (n - 1) / 2 - sc[0] * (sc[0] - 1) / 2 - sc[0] * sc[1] - sc[0] * sc[2]; ll res = m + sc[0] * (sc[0] - 1) / 2 * 2 + sc[0] * sc[1] * 3 + sc[0] * sc[2] * 2; cout << res << endl; }