import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import java.math.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long[] counts = new long[4];
        IntStream.range(0, n).forEach(i -> {
            counts[Math.min(3, sc.nextInt())]++;
        });
        long ans = counts[2] * counts[3] + counts[2] * (counts[2] - 1) / 2 + counts[3] * (counts[3] - 1) / 2
            + counts[1] * (counts[1] - 1) + counts[1] * counts[3] * 2 + counts[1] * counts[2] * 3;
        System.out.println(ans);
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}