#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream f("nrtri.in");
    ofstream g("nrtri.out");
    unsigned N;
    int a[100], i, nr=0, ok, aux;
    f>>N;
    for(i=0;i<N;i++)
        f>>a[i];
    do
    {
        ok=1;
        for(i=0;i<N-1;i++)
            if(a[i]>a[i+1])
        {
            ok=0;
            aux=a[i];
            a[i]=a[i+1];
            a[i+1]=aux;
        }
    }while(ok!=1);
    for(i=0;i<N-2;i++)
    {
        if(a[i]+a[i+1]>=a[i+2] && a[i]+a[i+2]>=a[i+1] && a[i+1]+a[i+2]>=a[i])
            nr++;
    }
    g<<nr;
    return 0;
}