#include<iostream.h>
#include<fstream.h>
main()
{long n,i,j,k,x=0,a[1000];
fstream f("nrtri.in",ios::in);
fstream g("nrtri.out",ios::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++)
   	for(k=j+1;k<=n;k++)
      	{if(a[i]>=a[j])
           {	if(a[k]>a[i])
            	{min1=a[j];med=a[i];max=a[k];}
            else
              if(a[k]>=a[j])
              	{min=a[j];med=a[k];max=a[i]};	}
              else {min=a[k];med=a[j];max=a[i];}}
            if(min+med>=max)
         	x++;
g<<x;
f.close();
g.close();
return 0;
}