using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] 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);
        Array.Sort(map, (l, r) => l[0].CompareTo(r[0]));
        var set = new HashSet<int>();
        foreach (var m in map)
        {
            set.Add(m[0]);
            set.Add(m[1]);
        }
        var list = new List<int>(set);
        list.Sort();
        var dic = new Dictionary<int, int>();
        for (var i = 0; i < list.Count; ++i) dic[list[i]] = i;
        var pos = 0;
        var dp = new int[list.Count + 1];
        for (var i = 0; i < dp.Length; ++i)
        {
            if (i > 0) dp[i] = Math.Max(dp[i], dp[i - 1]);
            while (pos < n && dic[map[pos][0]] == i)
            {
                dp[dic[map[pos][1]]] = Math.Max(dp[dic[map[pos][1]]], dp[i] + 1);
                ++pos;
            }
        }
        WriteLine(n - dp[^1]);
    }
}