import java.util.*;

public class Main {
    
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        long ans = 0;
        long[] cnt = new long[3];
        for( int i = 0; i < N; i++ ) {
            int a = sc.nextInt()-1;
            cnt[Math.min(2,a)]++;
        }
        
        ans += cnt[0]*(cnt[0]+cnt[2]-1);
        ans += cnt[0]*cnt[1]*3;
        ans += (cnt[1]+cnt[2])*(cnt[1]+cnt[2]-1)/2;
        System.out.println(ans);
        
    }
    
}