#include <iostream>
#include <string.h>
#include <algorithm>

using namespace std;

const int N = 1e5 + 10;
int a[N],b[N],c[N];
bool f[N];

int main(){
	int n,cnt = 0;
	
	cin >> n;
	memset(f,false,sizeof(f));
	memset(c,0,sizeof(c));
	
	for(int i = 0;i < n;i ++){
		cin >> a[i];
		f[a[i]] = true;
	}
	
	for(int i = 0,j = 0;i < n;i ++){
		cin >> b[i];
		if(f[b[i]]){
			c[j ++] = b[i];
			cnt ++;
		}
	}
	
	sort(c,c + n);
	
	cout << cnt << endl;
	for(int i = 0;i < n;i ++){
		if(c[i] != 0){
			cout << c[i] << " ";
		}
	}
	cout << endl;
	
	return 0;
}