Problem:
Score : 200 points

Problem Statement

We have sticks numbered 1, \cdots, N. The length of Stick i (1 \leq i \leq N) is L_i.

In how many ways can we choose three of the sticks with different lengths that can form a triangle?

That is, find the number of triples of integers (i, j, k) (1 \leq i < j < k \leq N) that satisfy both of the following conditions:

L_i, L_j, and L_k are all different.

There exists a triangle whose sides have lengths L_i, L_j, and L_k.

Constraints

1 \leq N \leq 100

1 \leq L_i \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
L_1 L_2 \cdots L_N

Output

Print the number of ways to choose three of the sticks with different lengths that can form a triangle.

Sample Input 1

5
4 4 9 7 5

Sample Output 1

5

The following five triples (i, j, k) satisfy the conditions: (1, 3, 4), (1, 4, 5), (2, 3, 4), (2, 4, 5), and (3, 4, 5).

Sample Input 2

6
4 5 4 3 3 5

Sample Output 2

8

We have two sticks for each of the lengths 3, 4, and 5. To satisfy the first condition, we have to choose one from each length.

There is a triangle whose sides have lengths 3, 4, and 5, so we have 2 ^ 3 = 8 triples (i, j, k) that satisfy the conditions.

Sample Input 3

10
9 4 6 1 9 6 10 6 6 8

Sample Output 3

39

Sample Input 4

2
1 1

Sample Output 4

0

No triple (i, j, k) satisfies 1 \leq i < j < k \leq N, so we should print 0.

Solution in C# (Mono-mcs 6.8.0.105) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel.Design;
using System.Globalization;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using System.Xml.Schema;
using static System.Console;

namespace ConsoleApp2
{
    class Program
    {
        static public int[] Sarray() { return ReadLine().Split().Select(int.Parse).ToArray(); }
        static public List<int> Slist() {
            var t = ReadLine();
            if (t.Trim().Length == 0) return new List<int>();
            return new List<int>(t.Split().Select(int.Parse)); }
        static void Main(string[] args)
        {
            var N = Sarray()[0];
            var Ln = Sarray();
            long ans = 0;
            for(var i=0;i<N;i++)
            {
                for(var j=i+1;j<N;j++)
                {
                    for(var k=j+1;k<N;k++)
                    {
                        if (Ln[i] != +Ln[j] && Ln[j] != +Ln[k] && Ln[k] != +Ln[i]
                            &&
                            Ln[i]+ Ln[j]> Ln[k] && Ln[j] + Ln[k] > Ln[i] && Ln[k] + Ln[i] > Ln[j]) ans++;
                    }
                }
            }
            WriteLine(ans);

        }
    }
}