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 (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>

#include <string.h>

int acs(const void* a, const void* b){
	
	return *(int *)a - *(int *)b;	
}

int main(){
	
	int i,j,k,N;
	char S[110];
	int cnt=0;
	int max=0;
	int ex=0;
	int L[110];
	scanf("%d",&N);
	
	for(i=0;i<N;i++){
		scanf("%d",L+i);//printf("%d:::a\n",i);
	}
	qsort(L,N,sizeof(int),acs);	
	
	for(i=0;i<N-2;i++){
		//printf("%d:::\n",i);
		for(j=i+1;j<N-1;j++){
			if(L[i]!=L[j])
			for(k=j+1;k<N;k++){
				if(L[j]!=L[k]){
					//printf("%d\n",abs(L[j]-L[k]));
					if(abs(L[j]-L[k])<L[i] && L[i]<(L[j]+L[k])){
						cnt++;
						//printf("%d,%d,%d\n",L[i],L[j],L[k]);
					}
				}
			}
			
		}
	}
	printf("%d\n",cnt);
	return 0;
}