#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>

using namespace std;
using ll = long long;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    ll N;
    cin >> N;
    vector<ll> A(N), B(N - 1);

    for (ll &x : A) cin >> x;
    for (ll &x : B) cin >> x;

    sort(A.begin(), A.end());
    sort(B.begin(), B.end());

    ll min_sadness = 0;
    for (ll i = 0; i < N - 1; i++) {
        min_sadness += abs(A[i] - B[i]);
    }

    vector<ll> possible_lengths = {A[N - 1]};
    ll current_sadness = min_sadness;

    for (ll i = N - 2; i >= 0; i--) {
        current_sadness += abs(A[i + 1] - B[i]) - abs(A[i] - B[i]);

        if (current_sadness < min_sadness) {
            min_sadness = current_sadness;
            possible_lengths = {A[i]};
        } else if (current_sadness == min_sadness) {
            possible_lengths.push_back(A[i]);
        }
    }

    sort(possible_lengths.begin(), possible_lengths.end());
    possible_lengths.erase(unique(possible_lengths.begin(), possible_lengths.end()), possible_lengths.end());

    cout << possible_lengths.size() << "\n";
    for (ll x : possible_lengths) cout << x << " ";
    cout << "\n";

    return 0;
}