#include <stdio.h>
int main()
{
	freopen("nrtri.in","r",stdin);
	freopen("nrtri.out","w",stdout);
	int i,n,e[30001],j,t,s=0;
	scanf("%d",&n);
	for (i=1; i<=30000; i++)
		e[i]=0;
	for (i=1; i<=n; i++)
	{
		scanf("%d",&t);
	    e[t]++;
	}
	for (i=1; i<=29998; i++)
	{
		if (e[i])
			for (j=i+1; j<=29999; j++)
				if (e[j])
					for (t=j+1; t<=30000; t++)
						if (e[t])
							if (i+j>=t)
								s++;
	}
	printf("%d",s);
	return 0;
}