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# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Linq;

namespace abc175.b
{
    class Program
    {
        static void Main(string[] args)
        {
            int num = getIntParam();
            long[] paramArray = getLongParams();

            int ret = 0;
            for (int i = 0; i < num; i++)
            {
                for (int j = i + 1; j < num; j++)
                {
                    for (int k = j + 1; k < num; k++)
                    {
                        long[] comb = new long[] { paramArray[i], paramArray[j], paramArray[k] };
                        Array.Sort(comb);

                        if ((comb[0] != comb[1]) && (comb[0] != comb[2]) && (comb[1] != comb[2]))
                        {
                            if (comb[0] + comb[1] > comb[2])
                            {
                                ret++;
                            }
                        }
                    }
                }
            }
            Console.WriteLine(ret);
        }

        //↓↓↓ shared function ↓↓↓
        static int getIntParam()
        {
            return int.Parse(Console.ReadLine());
        }
        static int[] getIntParams()
        {
            return Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();
        }
        static long getLongParam()
        {
            return long.Parse(Console.ReadLine());
        }
        static long[] getLongParams()
        {
            return Console.ReadLine().Split(' ').Select(i => long.Parse(i)).ToArray();
        }
        static string getStringParam()
        {
            return Console.ReadLine();
        }
        static string[] getStringParams()
        {
            return Console.ReadLine().Split(' ');
        }
    }
}