#include <bits/stdc++.h>
#define SZ(x) (int) x.size() - 1
#define all(x) x.begin(), x.end()
#define ms(x, y) memset(x, y, sizeof x)
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
template <typename T> void chkmax(T& x, T y) { x = max(x, y); }
template <typename T> void chkmin(T& x, T y) { x = min(x, y); }
template <typename T> void read(T &x) {
	x = 0; int f = 1; char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') f = -f;
	for (; isdigit(c); c = getchar()) x = x * 10 + c - '0';
	x *= f;
}
const int N = 110, MOD = 998244353;
template <typename T1, typename T2> void add(T1& x, T2 y) { x = (x + y) % MOD; }
int n, m, a[N], p[N], f[N][N], q[N], s[N], CC[N][N], fac[N], se[N];
int C(int x, int y) {
	return x < y ? 0 : CC[x][y];
}
void init(int n) {
	CC[0][0] = fac[0] = 1;
	F(i, 1, n) {
		fac[i] = (ll) fac[i - 1] * i % MOD;
		CC[i][0] = 1;
		F(j, 1, i) CC[i][j] = (CC[i - 1][j] + CC[i - 1][j - 1]) % MOD;
	}
}
signed main() {
	init(105);
	read(n);
	// cout << C(2, 1) << endl;
	F(i, 1, n) read(a[i]), se[i] = 1;
	F(i, 1, n) {
		int x; read(x);
		p[a[i]] = x;
		if (x) se[x] = 0;
	}
	F(i, 1, n + 1) se[i] += se[i - 1];
	int ss = 0;
	F(i, 1, n) {
		if (p[i]) {
			q[++m] = p[i];
			s[m] = s[m - 1] + ss;
			ss = 0;
		} else ss++;
	} q[++m] = n + 1;
	s[m] = s[m - 1] + ss;
	int tot = s[m];
	f[0][0] = 1;
	// F(i, 1, m) cout << q[i] << " " << s[i] << endl; cout << endl;
	F(i, 1, m)
		F(j, 0, i - 1)
			if (q[i] > q[j])
				F(k, 0, tot)
					F(l, 0, k)
						add(f[i][k], (ll) f[j][l] * C(s[i] - s[j], k - l) % MOD * C(se[q[i]] - se[q[j]], k - l));//, cout << i << " " << j << " " << k << " " << l << " " << f[j][l] << " " << s[i] << " " << s[j] << " " << q[i] << " " << q[j] << " " << C(s[i] - s[j], k - l) % MOD * C(q[i] - q[j], k - l) << endl;
	int ans = 0;
	// cout << tot << endl;
	F(i, 0, tot) add(ans, (ll) f[m][i] * fac[tot - i]);
	cout << ans;
	return 0;
}