#nullable enable

using System.Numerics;

void Run()
{
    var n = Int();
    var az = n.Repeat(Int).AsSpan();

    var bag = new Bag<int>();
    foreach (var a in az) bag.Add(a);
    var ans = 0L;
    az.Sort();
    foreach (var (k, c) in bag._dictionary)
    {
        var s = k * 2;
        var pass = -1;
        var fail = n;
        while (fail - pass > 1)
        {
            var mid = (pass + fail) >> 1;
            if (az[mid] < s) pass = mid;
            else fail = mid;
        }
        ans += (long)(pass - c + 1) * c * (c - 1) / 2;
    }
    Out(ans);
}

#region
AtCoderIO _io_;
var _backend_ = new StandardIOBackend();
_io_ = new(){ Backend = _backend_ };
Run();
_backend_.Flush();

string String() => _io_.Next();
int Int() => int.Parse(String());
void Out(object? x, string? sep = null) => _io_.Out(x, sep);

class AtCoderIO
{
    public required StandardIOBackend Backend { get; init; }

    Memory<string> _input = Array.Empty<string>();
    int _iter = 0;
    public string Next()
    {
        while (_iter >= _input.Length) (_input, _iter) = (Backend.ReadLine().Split(' '), 0);
        return _input.Span[_iter++];
    }

    public void Out(object? x, string? separator = null)
    {
        if (x == null) return;
        separator ??= Environment.NewLine;
        if (x is System.Collections.IEnumerable a and not string)
        {
            var objects = a.Cast<object>();
            if (separator == Environment.NewLine && !objects.Any()) return;
            x = string.Join(separator, objects);
        }
        Backend.WriteLine(x);
    }
}

class StandardIOBackend
{
    readonly StreamReader _sr = new(Console.OpenStandardInput());
    readonly StreamWriter _sw = new(Console.OpenStandardOutput()) { AutoFlush = false };
    public string ReadLine() => _sr.ReadLine()!;
    public void WriteLine(object? value) => _sw.WriteLine(value);
    public void Flush() => _sw.Flush();
}
#endregion

static class Extensions
{
    public static T[] Repeat<T>(this int time, Func<T> F) => Enumerable.Range(0, time).Select(_ => F()).ToArray();
}

class Bag<K> where K : notnull
{
    public readonly Dictionary<K, int> _dictionary = new();
    public void Add(K key)
    {
        var dictionary = _dictionary;
        if (dictionary.TryGetValue(key, out var count)) dictionary[key] = count + 1;
        else dictionary[key] = 1;
    }
    public void Remove(K key)
    {
        var dictionary = _dictionary;
        if (!dictionary.TryGetValue(key, out var count)) return;
        if (count == 1) dictionary.Remove(key);
        else dictionary[key] = count - 1;
    }
    public int this[K key] => _dictionary.TryGetValue(key, out var count) ? count : 0;
    public int CountKeys => _dictionary.Count;
}