/*
stacking
public class stacking {

}

*/

import java.util.*;
import java.io.*;

public class stacking {
	public static void main(String[] args) throws Exception {
		Scanner in = new Scanner(new File("stacking.in"));
		int[] stacks = new int[in.nextInt()];
		for(int i = 1; i<= in.nextInt(); i++) {
			int start = in.nextInt();
			int end = in.nextInt();
			for(int j = start; j<=end; j++) {
				stacks[j-1]++;
			}
		}
		in.close();

		Arrays.sort(stacks);

		int result = stacks[stacks.length/2];
		PrintWriter out = new PrintWriter(new File("stacking.out"));
		System.out.println(result);
		out.println(result);
		out.close();
	}

}

//shou