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

class Solver {
	private int[] a, u, d;
	private int n;

	private Solver(int[] u, int[] d) {
		if(u.length != d.length) {
			throw new IllegalArgumentException("Length mismatch");
		}

		this.n = u.length;
		this.a = new int[n];
		this.u = u;
		this.d = d;

		for(int i = 0; i < n; i++) {
			a[i] = 0;
		}
	}

	private int solveLower(int m, int k) {
		int[] u = new int[n];
		int[] d = new int[n];

		int ui = 1;
		int di = 1;
		for(int i = n - 1; i >= 0; i--) {
			u[i] = ui;
			d[i] = di;
			if(a[i] == 0 || a[i] > m) {
				ui = 1;
				++di;
			}
			else {
				di = 1;
				++ui;
			}
		}

		boolean flag = true;
		int c = 0;
		for(int i = 0; i < n; i++) {
			if(flag && a[i] == 0 && u[i] == this.u[i] && d[i] == this.d[i]) {
				a[i] = m;
				c += solve(k + 1);
				a[i] = 0;
				flag = false;
			}
			if(a[i] != 0 && a[i] < m) {
				flag = true;
			}
		}

		return c;
	}

	private int solveUpper(int m, int k) {
		int[] u = new int[n];
		int[] d = new int[n];

		int ui = 1;
		int di = 1;
		for(int i = n - 1; i >= 0; i--) {
			u[i] = ui;
			d[i] = di;
			if(a[i] == 0 || a[i] < m) {
				di = 1;
				++ui;
			}
			else {
				ui = 1;
				++di;
			}
		}

		boolean flag = true;
		int c = 0;
		for(int i = 0; i < n; i++) {
			if(flag && a[i] == 0 && u[i] == this.u[i] && d[i] == this.d[i]) {
				a[i] = m;
				c += solve(k + 1);
				a[i] = 0;
				flag = false;
			}
			if(a[i] != 0 && a[i] > m) {
				flag = true;
			}
		}

		return c;
	}

	private int solve(int k) {
		if(k == n) {
			return 1;
		}

		if(k % 2 == 0) {
			return solveLower(k / 2 + 1, k);
		}
		else {
			return solveUpper(n - k / 2, k);
		}
	}

	public static int solve(int[] u, int[] d) {
		Solver s = new Solver(u, d);
		return s.solve(0);
	}
}

public class updown {
	public static void main(String[] args) throws Exception {
		BufferedReader br = null;

		try {
			br = new BufferedReader(new InputStreamReader(System.in));

			while(true) {
				int n = Integer.parseInt(br.readLine());
				if(n == 0) break;

				StringTokenizer tok;

				tok = new StringTokenizer(br.readLine());
				int[] u = new int[n];
				for(int i = 0; i < n; i++) {
					u[i] = Integer.parseInt(tok.nextToken());
				}

				tok = new StringTokenizer(br.readLine());
				int[] d = new int[n];
				for(int i = 0; i < n; i++) {
					d[i] = Integer.parseInt(tok.nextToken());
				}

				long st = System.currentTimeMillis();
				System.out.println(Solver.solve(u, d));
				long et = System.currentTimeMillis();
				System.out.println((et - st) + "ms");
			}
		}
		finally {
			if(br != null) br.close();
		}
	}
}