#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int N;
int A[202020],B[202020];

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N) cin>>A[i];
	FOR(i,N-1) cin>>B[i];
	sort(A,A+N);
	sort(B,B+N-1);
	
	map<ll,set<int>> M;
	ll sum=0;
	FOR(i,N) sum+=abs(A[i]-B[i]);
	M[sum].insert(A[N-1]);
	for(i=N-2;i>=0;i--) {
		sum-=abs(A[i]-B[i]);
		sum+=abs(A[i+1]-B[i]);
		M[sum].insert(A[i]);
	}
	
	auto p=M.begin()->second;
	cout<<p.size()<<endl;
	FORR(c,p) cout<<c<<" ";
	cout<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}