#include<bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int>A(N);
    long long x = 0,y = 0;
    for(int i = 0; i < N; i++) {
        cin >> A[i];
        if(A[i] == 1) {
            x++;
        }
        if(A[i] == 2) {
            y++;
        }
    }
    long long tmp = (N-1)*N/2;
    long long ans = 0;
    ans += x*y*3;
    tmp -= x*y;
    ans += x*(N-y-1)*2;
    ans -= x*(x-1);
    tmp -= x*(N-y-1);
    tmp += x*(x-1)/2;
    ans += tmp;
    cout << ans << endl;
}