#include<iostream.h>
#include<fstream.h>
main()
{
long a[1000],max,i,j,k,l,m,n,sp,aux,valid,x;
fstream f("nrtri.in",ios::in);
fstream g("nrtri.out",ios::out);
f>>n;
for(i=1;i<=n;i++)
 f>>a[i];
i=1;j=2;k=3;sp=0;
f>>a[i];
 while(i<=(n-2))
   {
    while(j<n)
    {
     while(k<=n)
      {
       max=0;
       if((a[i]>=a[j])&&(a[i]>=a[k]))max=a[i];
       if((a[j]>=a[i])&&(a[j]>=a[k]))max=a[j];
       if((a[k]>=a[i])&&(a[k]>=a[j]))max=a[k];
       if(((a[i]+a[j]+a[k]) -max ) >=max )
	  { sp++;
      //    cout<<endl<<i<<" "<<j<<" "<<k;
	   }
       k++;
       };
    j++;k=j+1;
    };
  i++;j=i+1;k=i+2;
 }
// cout<<endl<<"sp = "<<sp;

g<<sp;


f.close();
g.close();
return 0;
}