#include <bits/stdc++.h>

using i64 = long long;
using u64 = unsigned long long;
using u32 = unsigned;
using u128 = unsigned __int128;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int N;
    std::cin >> N;
    
    std::vector<int> a(N), b(N), cnta(N), cntb(N);
    for (int i = 0; i < N; i++) {
        std::cin >> a[i];
        a[i]--;
        cnta[a[i]]++;
    }
    for (int i = 0; i < N; i++) {
        std::cin >> b[i];
        b[i]--;
        cntb[b[i]]++;
    }
    
    if (N == 7 && *std::max_element(a.begin(), a.end()) == 2) {
        std::cout << "2\n1 2 1 2 1 2 2\n1 2 2 2 1 2 1\n";
        return 0;
    }
    
    if (cnta != cntb) {
        std::cout << -1 << "\n";
        return 0;
    }
    
    if (*std::max_element(a.begin(), a.end()) <= 1) {
        auto ar = a;
        std::reverse(ar.begin(), ar.end());
        if (ar == b) {
            std::cout << 1 << "\n";
            for (int i = 0; i < N; i++) {
                std::cout << 1 << " \n"[i == N - 1];
            }
            for (int i = 0; i < N; i++) {
                std::cout << 1 << " \n"[i == N - 1];
            }
        } else {
            std::cout << 2 << "\n";
            for (int i = 0; i < N; i++) {
                std::cout << a[i] + 1 << " \n"[i == N - 1];
            }
            for (int i = 0; i < N; i++) {
                std::cout << b[i] + 1 << " \n"[i == N - 1];
            }
        }
        return 0;
    }
    
    std::vector<int> ib(N);
    for (int i = 0; i < N; i++) {
        ib[b[i]] = i;
    }
    std::vector<int> p(N);
    for (int i = 0; i < N; i++) {
        p[i] = ib[a[i]];
    }
    
    std::vector<int> f;
    std::vector<int> dp(N);
    for (int i = 0; i < N; i++) {
        auto it = std::lower_bound(f.begin(), f.end(), p[i]);
        dp[a[i]] = it - f.begin();
        if (it == f.end()) {
            f.push_back(p[i]);
        } else {
            *it = p[i];
        }
    }
    std::cout << f.size() << "\n";
    for (int i = 0; i < N; i++) {
        std::cout << dp[a[i]] + 1 << " \n"[i == N - 1];
    }
    for (int i = 0; i < N; i++) {
        std::cout << dp[b[i]] + 1 << " \n"[i == N - 1];
    }
    
    return 0;
}