using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
    static void Solve()
    {
        var N = sc.ReadInt();
        var AB = sc.ReadTupArray(N);
        var CD = sc.ReadTupArray(N);
        var ff = new FordFulkerson(2 * N + 2);
        for (int i = 0; i < N; i++)
        {
            var ab = AB[i];
            for (int j = 0; j < N; j++)
            {
                var cd = CD[j];
                if (ab.Item1 < cd.Item1 && ab.Item2 < cd.Item2)
                {
                    ff.AddEdge(i, j + N, 1);
                }
            }
        }
        var s = 2 * N;
        var t = 2 * N + 1;
        for (int i = 0; i < N; i++)
        {
            ff.AddEdge(s, i, 1);
        }
        for (int i = 0; i < N; i++)
        {
            ff.AddEdge(i + N, t, 1);
        }
        var ans = ff.MaxFlow(s, t);
        Console.WriteLine(ans);
    }

    class FordFulkerson
    {
        public int N;
        public List<Edge>[] G;
        private bool[] Visited;
        public FordFulkerson(int n)
        {
            this.N = n;
            this.G = new List<Edge>[N];
            for (int i = 0; i < N; i++) G[i] = new List<Edge>();
        }
        public void AddEdge(int from, int to, long cap)
        {
            // 逆辺を用意しておく
            this.G[from].Add(new Edge(to, cap, this.G[to].Count));
            this.G[to].Add(new Edge(from, 0, this.G[from].Count - 1));
        }
        public long MaxFlow(int s, int t)
        {
            var res = 0L;
            long f = 0;
            do
            {
                Visited = new bool[N];
                f = Dfs(s, t, long.MaxValue);
                res += f;
            } while (f > 0);
            return res;
        }
        public long Dfs(int now, int goal, long flow)
        {
            if (now == goal) return flow;
            Visited[now] = true;
            for (int i = 0; i < G[now].Count; i++)
            {
                var e = G[now][i];
                var next = e.To;
                var cap = e.Capacity;
                if (Visited[next] || cap == 0) continue;
                var nf = Math.Min(flow, cap);
                var f = Dfs(next, goal, nf);
                if (f > 0)
                {
                    e.Capacity -= f;
                    G[e.To][e.Rev].Capacity += f;
                    return f;
                }
            }
            return 0;
        }
        public class Edge
        {
            public int To;
            public long Capacity;
            public int Rev;
            public Edge(int to, long cap, int rev)
            {
                this.To = to;
                this.Capacity = cap;
                this.Rev = rev;
            }
        }
    }
    static Scanner sc = new Scanner();
}
class Scanner
{
    string[] S = new string[0];
    int Index = 0;
    char[] Separators = new char[] { ' ' };

    public string Next()
    {
        if (this.Index < this.S.Length) return this.S[this.Index++];
        var line = "";
        while (line == "") line = Console.ReadLine();
        this.S = line.Split(this.Separators, StringSplitOptions.RemoveEmptyEntries);
        if (this.S.Length == 0) return this.Next();
        this.Index = 0;
        return this.S[this.Index++];
    }
    public string ReadStr()
    {
        return this.Next();
    }
    public char ReadChar()
    {
        return this.Next()[0];
    }
    public int ReadInt()
    {
        return int.Parse(this.Next());
    }
    public uint ReadUInt()
    {
        return uint.Parse(this.Next());
    }
    public long ReadLong()
    {
        return long.Parse(this.Next());
    }
    public double ReadDouble()
    {
        return double.Parse(this.Next());
    }
    public Tuple<int, int> ReadTup(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add);
    }
    public Tuple<long, long> ReadTupLong(int add = 0)
    {
        return Tuple.Create(this.ReadLong() + add, this.ReadLong() + add);
    }
    public Tuple<int, int, int> ReadTup3(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
    }
    public Tuple<int, int, int, int> ReadTup4(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
    }
    public int[] ReadIntArray(int n)
    {
        var array = new int[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadInt();
        }
        return array;
    }
    public long[] ReadLongArray(int n)
    {
        var array = new long[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadLong();
        }
        return array;
    }
    public double[] ReadDoubleArray(int n)
    {
        var array = new double[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadDouble();
        }
        return array;
    }
    public char[] ReadCharArray(int n)
    {
        var array = new char[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadChar();
        }
        return array;
    }
    public string[] ReadStrArray(int n)
    {
        var array = new string[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadStr();
        }
        return array;
    }
    public Tuple<long, long>[] ReadTupLongArray(int n, int add = 0)
    {
        var array = new Tuple<long, long>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTupLong(add);
        }
        return array;
    }
    public Tuple<int, int>[] ReadTupArray(int n, int add = 0)
    {
        var array = new Tuple<int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup(add);
        }
        return array;
    }
    public Tuple<int, int, int>[] ReadTup3Array(int n, int add = 0)
    {
        var array = new Tuple<int, int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup3(add);
        }
        return array;
    }
    public Tuple<int, int, int, int>[] ReadTup4Array(int n, int add = 0)
    {
        var array = new Tuple<int, int, int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup4(add);
        }
        return array;
    }
}


Measured memory_bytes: 11348