#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");

int n,i,a[805],N,j=1,b[805],Nr;

void Read()
{
    fin>>n;
    for(i=1;i<=n;i++)
    fin>>a[i];
}

void SolveandPrint()
{
    for(i=1;i<=n;i++)
		for(int i=1; i<=n-1; i++)
		{
			if(a[i]>a[i+1])
			{swap(a[i],a[i+1]);
			}
		}
    for(i=3;i<=n;i++)
        if((a[i-2]+a[i-1])>=a[i] && (a[i-1]+a[i]>=a[i-2]) && (a[i]+a[i-2]>=a[i-1]))
        Nr++;
        fout<<Nr;
}
int main()
{
    Read();
    SolveandPrint();
}