#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> PP;
// #define MOD 1000000007
#define MOD 998244353
#define INF 2305843009213693951
#define PI 3.141592653589
#define setdouble setprecision
#define REP(i,n) for(ll i=0;i<(n);++i)
#define OREP(i,n) for(ll i=1;i<=(n);++i)
#define RREP(i,n) for(ll i=(n)-1;i>=0;--i)
#define ORREP(i,n) for(ll i=(n);i>=1;--i)
#define rep(i,a,b) for(ll i=(a);i<=(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define chmin(k,m) k = min(k,m)
#define chmax(k,m) k = max(k,m)
#define GOODBYE do { cout << "-1" << endl; return 0; } while (false)
#define MM <<" "<<
#define Endl endl


int main(void){
    //cin.tie(nullptr);
    //ios::sync_with_stdio(false);
    
    ll N;
    cin >> N;
    // vector<pair<ll,ll>> Y(N);
    vector<ll> A(N),B(N-1);
    REP(i,N){
      ll a;
      cin >> a;
      A[i] = a;
    }
    REP(i,N-1){cin >> B[i];}
    sort(ALL(A));
    sort(ALL(B));

    vector<ll> L(N-1),R(N-1);
    REP(i,N-1){
      L[i] = abs(A[i]-B[i]);
    }
    REP(i,N-1){
      R[i] = abs(A[i+1]-B[i]);
    }
    REP(i,N-2){
      L[i+1] += L[i]; 
    }
    RREP(i,N-2){
      R[i] += R[i+1]; 
    }
    
    // REP(i,N-1){cout << L[i] << " ";}cout << endl;
    // REP(i,N-1){cout << R[i] << " ";}cout << endl;
    

    vector<ll> S(N);
    S[0] = R[0];
    S[N-1] = L[N-2];
    REP(i,N-2){
        S[i+1] = L[i]+R[i+1];
    }
    
    ll m = INF;
    REP(i,N){m = min(m,S[i]);}
    // cout << m << endl;
    // REP(i,N){cout << S[i] << " ";}cout << endl;

    ll count = 0;
    REP(i,N){if(m==S[i])count++;}
    
    multiset<ll> Ans;
    // REP(i,N){Ans.insert(A[i]);}
    REP(i,N){
      if(m==S[i]){
        // Ans.erase(Ans.find(A[i]));
        Ans.insert(A[i]);
      }
    }
    
    set<ll> ans;
    for(ll a:Ans){
        ans.insert(a);
    }

    cout << ans.size() << endl;
    for(ll s:ans){
        cout << s << " ";
    }cout << endl;

    return 0;
    
}