import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int q = sc.nextInt();
		Obj[] arr = new Obj[q];
		for (int i = 0; i < q; i++) {
			Obj o = new Obj();
			o.a = sc.nextInt();
			o.b = sc.nextInt();
			arr[i] = o;
		}
		sc.close();

		Arrays.sort(arr, (o1, o2) -> {
			if (o1.a != o2.a) {
				return o1.a - o2.a;
			}
			return o2.b - o1.b;
		});

		int[] dp = new int[m + 1];
		for (int i = 1; i <= m; i++) {
			dp[i] = Integer.MAX_VALUE;
		}

		for (int i = 0; i < q; i++) {
			int idx = Arrays.binarySearch(dp, arr[i].b);
			if (idx < 0) idx = ~idx;
			dp[idx] = arr[i].b;
		}

		int lis = Arrays.binarySearch(dp, Integer.MAX_VALUE - 1);
		if (lis < 0) {
			lis = ~lis;
			lis--;
		}
		System.out.println(lis);
	}

	static class Obj {
		int a, b;
	}
}