C++ :

#include<iostream>
using namespace std;

int main(){
	
	int l;
	cin>>l;
	int i,j,k;
	int s;
	s=0; 
	
	
	for(i=1;i<=l/3;i++){
		for(j=i;j<=l/2;j++){
			k=l-i-j;
			if((k==j && j!=i) || k>j){
				if(i+j>k && i+k>j && j+k>i){
						s++;
				}
			
			}
		}
	} 
	
	cout<<s<<endl;
}

Python :

L=int(input())
count=0
for i in range(1,L-1):
    for j in range(i,L-i):
        k=L-i-j
        if (k>=j and i+j>k and i+k>j and j+k>i):
            if (i==j and i==k):
                continue
            else:
                count=count+1
print(count)