import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;

public class Main {

	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		MyInput in = new MyInput(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskX solver = new TaskX();
		solver.solve(1, in, out);
		out.close();
	}

	static int INF = 1 << 30;
	static long LINF = 1L << 55;
	static int MOD = 1000000007;
	static int[] mh4 = { 0, -1, 1, 0 };
	static int[] mw4 = { -1, 0, 0, 1 };
	static int[] mh8 = { -1, -1, -1, 0, 0, 1, 1, 1 };
	static int[] mw8 = { -1, 0, 1, -1, 1, -1, 0, 1 };

	static class TaskX {

		public void solve(int testNumber, MyInput in, PrintWriter out) {

			int n = in.nextInt();
			int[] a = new int[n+1], b = new int[n+1], c = new int[n+1], d = new int[n+1];
			for (int i = 1; i <= n; i++) {
				a[i] = in.nextInt();
				b[i] = in.nextInt();
			}
			for (int i = 1; i <= n; i++) {
				c[i] = in.nextInt();
				d[i] = in.nextInt();
			}

			Dinic dinic = new Dinic(2*n+2);
			for (int i = 1; i <= n; i++) {
				for (int j = 1; j <= n; j++) {
					if (a[i] < c[j] && b[i] < d[j]) {
						dinic.addEdge(i, j+n, 1);
					}
				}
			}
			for (int i = 1; i <= n; i++) {
				dinic.addEdge(0, i, 1);
				dinic.addEdge(i+n, 2*n+1, 1);
			}

			out.println(dinic.maxFlow(0, 2*n+1));

		}
	}

	static class Dinic {

		private class Edge {
			int to, cap, rev;

			public Edge(int to, int cap, int rev) {
				this.to = to;
				this.cap = cap;
				this.rev = rev;
			}
		}

		ArrayList<ArrayList<Edge>> g;
		int[] level, iter;

		public Dinic(int V) {
			g = new ArrayList<>(V);
			for (int i = 0; i < V; i++) g.add(new ArrayList<>());
			level = new int[V];
			iter = new int[V];
		}

		void addEdge(int from, int to, int capacity) {
			g.get(from).add(new Edge(to, capacity, g.get(to).size()));
			g.get(to).add(new Edge(from, 0, g.get(from).size() -1));
		}

		void bfs(int s) {
			Arrays.fill(level, -1);
			ArrayDeque<Integer> q = new ArrayDeque<>();
			level[s] = 0;
			q.add(s);

			while (!q.isEmpty()) {
				int v = q.poll();
				for (Edge e : g.get(v)) {
					if (e.cap > 0 && level[e.to] < 0) {
						level[e.to] = level[v] + 1;
						q.add(e.to);
					}
				}
			}
		}

		int dfs(int v, int t, int f) {
			if (v == t) return f;
			for (int i = iter[v]; i < g.get(v).size(); i++) {
				Edge e = g.get(v).get(i);
				if (e.cap > 0 && level[v] < level[e.to]) {
					int d = dfs(e.to, t, Math.min(f, e.cap));
					if (d > 0) {
						e.cap -= d;
						g.get(e.to).get(e.rev).cap += d;
						return d;
					}
				}
			}
			return 0;
		}

		int maxFlow(int s, int t) {
			int flow = 0;
			while (true) {
				bfs(s);
				if (level[t] < 0) return flow;
				Arrays.fill(iter, 0);
				int f;
				while ((f = dfs(s, t, Integer.MAX_VALUE)) > 0) {
					flow += f;
				}
			}
		}
	}

	static class MyInput {
		private final BufferedReader in;
		private static int pos;
		private static int readLen;
		private static final char[] buffer = new char[1024 * 8];
		private static char[] str = new char[500 * 8 * 2];
		private static boolean[] isDigit = new boolean[256];
		private static boolean[] isSpace = new boolean[256];
		private static boolean[] isLineSep = new boolean[256];

		static {
			for (int i = 0; i < 10; i++) {
				isDigit['0' + i] = true;
			}
			isDigit['-'] = true;
			isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
			isLineSep['\r'] = isLineSep['\n'] = true;
		}

		public MyInput(InputStream is) {
			in = new BufferedReader(new InputStreamReader(is));
		}

		public int read() {
			if (pos >= readLen) {
				pos = 0;
				try {
					readLen = in.read(buffer);
				} catch (IOException e) {
					throw new RuntimeException();
				}
				if (readLen <= 0) {
					throw new MyInput.EndOfFileRuntimeException();
				}
			}
			return buffer[pos++];
		}

		public int nextInt() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			int i = 0;
			int ret = 0;
			if (str[0] == '-') {
				i = 1;
			}
			for (; i < len; i++)
				ret = ret * 10 + str[i] - '0';
			if (str[0] == '-') {
				ret = -ret;
			}
			return ret;
		}

		public long nextLong() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			int i = 0;
			long ret = 0;
			if (str[0] == '-') {
				i = 1;
			}
			for (; i < len; i++)
				ret = ret * 10 + str[i] - '0';
			if (str[0] == '-') {
				ret = -ret;
			}
			return ret;
		}

		public char nextChar() {
			while (true) {
				final int c = read();
				if (!isSpace[c]) {
					return (char) c;
				}
			}
		}

		public String nextString() {
			return new String(nextChars());
		}

		public char[] nextChars() {
			int len = 0;
			str[len++] = nextChar();
			len = reads(len, isSpace);
			return Arrays.copyOf(str, len);
		}

		public char[][] next2DChars(int h, int w) {
			char[][] s = new char[h][w];
			for (int i = 0; i < h; i++) {
				s[i] = nextChars();
			}
			return s;
		}

		int reads(int len, boolean[] accept) {
			try {
				while (true) {
					final int c = read();
					if (accept[c]) {
						break;
					}
					if (str.length == len) {
						char[] rep = new char[str.length * 3 / 2];
						System.arraycopy(str, 0, rep, 0, str.length);
						str = rep;
					}
					str[len++] = (char) c;
				}
			} catch (MyInput.EndOfFileRuntimeException e) {
			}
			return len;
		}

		public int[] nextIntArray(final int n) {
			final int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt();
			}
			return res;
		}

		public int[] nextIntArray1Index(final int n) {
			final int[] res = new int[n + 1];
			for (int i = 1; i < n + 1; i++) {
				res[i] = nextInt();
			}
			return res;
		}

		public int[] nextIntArrayDec(final int n) {
			final int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt() - 1;
			}
			return res;
		}

		public long[] nextLongArray(final int n) {
			final long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong();
			}
			return res;
		}

		public long[] nextLongArray1Index(final int n) {
			final long[] res = new long[n + 1];
			for (int i = 1; i < n + 1; i++) {
				res[i] = nextLong();
			}
			return res;
		}

		public long[] nextLongArrayDec(final int n) {
			final long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong() - 1;
			}
			return res;
		}

		public double nextDouble() {
			return Double.parseDouble(nextString());
		}

		public double[] nextDoubleArray(int n) {
			double[] res = new double[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextDouble();
			}
			return res;
		}

		static class EndOfFileRuntimeException extends RuntimeException {
		}

	}

}


Measured memory_bytes: 24276