#include <iostream>
#include<algorithm>
#include<fstream>
using namespace std;
int N,v[800],nr,i,j;
int main()
{
    ifstream fin;
    fin.open("nrtri.in");
    ofstream fout;
    fout.open("nrtri.out");
    fin>>N;
    nr=0;
    for(i=1;i<=N;i++)
        fin>>v[i];
    sort(v,v+(N+1));
    for(i=1;i<=N;i++)
    {
        j=1;
        while((j==i||j==i+1)&&j<=N)
        {
            j=j+1;
        }
        if(i>=2)
        {
            j=i+2;
        }
        if(v[i]+v[i+1]>=v[j]&&v[i]+v[j]>=v[i+1]&&v[i+1]+v[j]>=v[i])
            nr=nr+1;
    }
    fout<<nr;
    fout.close();
    return 0;
}