#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
using Bint = mp::cpp_int;
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int n;
    cin >> n;
    vector<int> a(n);
    vector<int> b(n-1);
    rep(i,n) cin >> a[i];
    rep(i,n-1) cin >> b[i];
    ll now = 0;
    sort(a.begin(),a.end());
    sort(b.begin(),b.end());
    rep(i,n-1) now += abs(a[i]-b[i]);
    map<ll, vector<int>> mp;
    mp[now].push_back(a[n-1]);
    for(int i=n-2;i>=0;i--){
        now -= abs(b[i]-a[i]);
        now += abs(b[i]-a[i+1]);
        mp[now].push_back(a[i]);
    }
    dbg(mp);
    auto vs = (*mp.begin()).second;
    sort(vs.begin(),vs.end());
    vs.erase(unique(vs.begin(),vs.end()),vs.end());
    cout << vs.size() << endl;
    rep(i,vs.size()) {
        cout << vs[i] << (i+1==vs.size()?"\n":" ");
    }
    return 0;
}