import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

class Main {
	public static void main(String[] args) throws Exception {
		new Main().run();
	}
	
	void run() {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int[] cnt=new int[101];
		for(int i=0;i<N;++i) {
			int a=sc.nextInt();
			cnt[a]++;
		}
		long[] dp=new long[3];
		for(int i=0;i<cnt.length;++i) {
			dp[2]+=dp[1]*cnt[i];
			dp[1]+=dp[0]*cnt[i];
			dp[0]+=cnt[i];
		}
		System.out.println(dp[2]);
		
	}
	
	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
	
}