import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		int h = Integer.parseInt(sa[1]);
		int[] c = new int[h + 1];
		for (int i = 0; i < n; i++) {
			sa = br.readLine().split(" ");
			int a = Integer.parseInt(sa[0]);
			int b = Integer.parseInt(sa[1]) + 1;
			c[a]++;
			c[b]--;
		}
		br.close();

		int ans = c[0];
		for (int i = 1; i <= h; i++) {
			c[i] += c[i - 1];
			ans = Math.max(ans, c[i]);
		}
		System.out.println(ans);
	}
}