#include <bits/stdc++.h>

using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int v[100001], n, nr = 0;
void cautbin(int x, int y)
{
    int st = x, dr = y;
    while(st < dr)
    {

        int mij = (st + dr) / 2;
        if(v[mij] + v[st] <= v[dr])
        {
            nr++;
            st = mij;
        }
        else{
            dr = mij;
            st = x;
    }}
}
int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++)
        fin >> v[i];
    sort(v + 1, v + n + 1);
    cautbin(1, n);
    fout << nr;
    return 0;
}