#include<iostream.h>
#include<fstream.h>
ifstream f("D:\\nrtri.in");
ofstream g("D:\\nrtri.out");

int main()
{
     int n,i,v[100],a,b,c,nr=0;
    f >> n;
for (i=1; i<=n; i++)
    f >> v[i];
   for (i=3; i<n; i++)
	  for (j=i+1; j<=n; 
	   
   {
	   a=v[i];
	   b=v[i-1];
	   c=v[i-2];
	   if (a+c>b && a+b>c && b+c>a)
		   nr++;
   }
   g << nr;
   g.close();
}