#include <vector>
#include <iostream>
using namespace std;
vector<int> unite(int* a, int n, int* b, int m){
	vector <int> ans;
	int j = 0;
	for(int i = 0; i < n; i++){
		while(j < m && b[j] < a[i]){
			ans.push_back(b[j]);
			j++;
		}
		if(j < m && b[j] == a[i])
			j++;
		ans.push_back(a[i]);
	}
	while(j < m){
		ans.push_back(b[j]);
		j++;
	}
	return ans;
}
int main(){
	int n;
	cin >> n;
	int *a = new int[n];
	for(int i=0;i<n;i++)
		cin >> a[i];

	int m;
	cin >> m;
	int *b = new int[m];
	for(int i=0;i<n;i++)
		cin >> b[i];

	vector <int> ans;
	ans = unite(a,n,b,m);

	cout << ans.size() << endl;
	for(int i = 0; i < ans.size() ; i++){
		cout << it << " ";

	return 0;
}