import java.io.*; import java.util.*; public class Main { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); TreeMap counts = new TreeMap<>(); for (int i = 0; i < n; i++) { int x = sc.nextInt(); counts.put(x, counts.getOrDefault(x, 0) + 1); } long mother = 1; long child = 1; for (int x : counts.values()) { for (int i = 0; i < x; i++) { mother *= n - i; child *= x - i; } n -= x; } System.out.println(mother / child); } } 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(); } }