#include <fstream>
#define N 805
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");

int Triunghi(int a, int b, int c)
{
    if(c< a+b || a< b+c || b< a+c)
        return 1;
    return 0;
}

void Sortare(int n, int a[])
{
    int i, ordo=0;
    int aux;
    while(ordo==0)
    {
        ordo=1;
        for(i=1;i<=n-1;i++)
            if(a[i]>a[i+1])
        {
            aux=a[i];
            a[i]=a[i+1];
            a[i+1]=aux;
            ordo=0;
        }
    }
}


int main()
{   int n, a[N], i, j, ct=0;
    fin >> n;
    for(i=1; i<=n ;i++)
        fin>>a[i];

    Sortare(n, a);
    for(i=1;i<=n-2;i++)
        if(Triunghi(a[i], a[i+1], a[i+2])==1)
           ct++;

    fout<<ct;

    return 0;
}