using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    static long[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var map = NArr(n);
        var ans = 0;
        for (var i = 0; i + 1 < n; ++i)
        {
            var list = new List<Rad>();
            for (var j = 0; j < n; ++j)
            {
                if (i == j) continue;
                list.Add(new Rad(map[j][0] - map[i][0], map[j][1] - map[i][1]));
            }
            list.Sort((l, r) =>
            {
                var d = l.Ch.CompareTo(r.Ch);
                if (d != 0) return d;
                return l.Pa.CompareTo(r.Pa);
            });
            for (var j = 0; j + 1 < list.Count; ++j)
            {
                if (list[j].Ch == list[j + 1].Ch && list[j].Pa == list[j + 1].Pa)
                {
                    ++ans;
                    break;
                }
            }
        }
        WriteLine(ans);
    }
    class Rad
    {
        public long Ch;
        public long Pa;
        public Rad(long x, long y)
        {
            var gcd = GCD(x, y);
            Ch = y / gcd;
            Pa = x / gcd;
        }
    }
    static long GCD(long a, long b)
    {
        if (a < 0) a = -a;
        if (b < 0) b = -b;
        if (a < b) return GCD(b, a);
        if (b == 0) return a;
        if (a % b == 0) return b;
        return GCD(b, a % b);
    }
}