#include <bits/stdc++.h>
    using namespace std;
    #include <math.h>
    #include <iomanip>
    #include <cstdint>
    #include <string>
    #include <sstream>
    template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
    template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
    #define rep(i,n) for (int i = 0; i < (n); ++i)
    typedef long long ll;
    using P=pair<int,int>;
    const int INF=1001001001;
    const int mod=1e9+7;
    
    int main(){
      int n;
      cin>>n;
      ll cnt1=0,cnt2=0;
      rep(i,n){
        int a;
        cin>>a;
        if(a==1){cnt1++;}
        if(a==2){cnt2++;}
      }
      ll ans=0;
      ll p=n-cnt1,p2=n-cnt1-cnt2;
      ans+=p*(p-1)/2;
      ans+=2*cnt1*(cnt1-1)/2+cnt1*p2;
      ans+=3*cnt1*cnt2;
      cout<<ans<<endl;
      return 0;
    }