#include<fstream.h>
int main()
   {ifstream f("nrtri.in");
   ofstream g("nrtri.out");
   int n,a[30000],i,j,k,nr=0;
   f>>n;
   for(i=1;i<=n;i++)
      f>>a[i];
   for(i=1;i<=n;i++)
      for(j=1;j<=n;j++)
	 for(k=1;k<=n;k++)
	    if(a[i]+a[j]>=a[k] && a[i]+a[k]>=a[j] && a[j]+a[k]>=a[i]) nr++;
   g<<nr;}