#include<fstream>
using namespace std;
int nr,n,i,j,aux,l,a[8001];
int main()
{
	ifstream f("nrtri.in");
	ofstream g("nrtri.out");
	f>>n;
	for(i=1;i<=n;i++)
		f>>a[i];
	for(i=1;i<=n-1;i++)
		for(j=i+1;j<=n;j++)
			if(a[i]>a[j])
			{	
				aux=a[i];
				a[i]=a[j];
				a[j]=aux;
			}
			for(i=1;i<=n;i++)
				for(j=i+1;j<=n;j++)
					for(l=j+1;l<=n;l++)
						if(a[i]+a[j]>=a[l])
							nr++;
								g<<nr;
}