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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A = sc.nextInt();
		int[] cardA = new int[A];
		for (int i = 0; i < cardA.length; i++) {
			cardA[i] = sc.nextInt();
		}
		int C = sc.nextInt();
		int[] cardC = new int[C];
		for (int i = 0; i < cardC.length; i++) {
			cardC[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(cardA);
		Arrays.sort(cardC);

		boolean[] usedA = new boolean[A];

		int ans = 0;
		for (int n = 0; n < N; n++) {
			int curC = n % C;
			if (n % A == 0) {
				Arrays.fill(usedA, false);
			}

			boolean used = false;
			for (int i = 0; i < usedA.length; i++) {
				if (!usedA[i] && cardA[i] > cardC[curC]) {
					used = true;
					usedA[i] = true;
					break;
				}
			}
			if (used) {
				ans++;
				continue;
			}

			for (int i = 0; i < usedA.length; i++) {
				if (!usedA[i]) {
					usedA[i] = true;
					break;
				}
			}
		}
		System.out.println(ans);
	}

}