import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        long n = sc.nextInt();
        long one = 0;
        long two = 0;
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            if (x == 1) {
                one++;
            } else if (x == 2) {
                two++;
            }
        }
        long oneone = one * (one - 1) / 2;
        long onetwo = one * two;
        long others = n * (n - 1) / 2 - oneone - onetwo;
        System.out.println(oneone * 2 + onetwo * 3 + others);
    }
}
    
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}