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(); } }