#include<bits/stdc++.h>
using namespace std;
bool cmp(int x,int y){
	return x>y;
}
int a[1000]={0},b[1000]={0},s[1000]={0},h[2000];
int main(){
	int i,n,j,m,o=1,k=0,l=1;
	cin>>m>>n;
	for(i=0;i<m;i++){
		cin>>a[i];
		h[l]=a[i];
		l++;
	}l++;
	for(j=0;j<n;j++){
		cin>>b[j];
		h[l]=b[j];
		l++;
	}
	sort(h,h+l);
	for(i=1;i<l;){
		if((h[i]==h[i+1])&&(h[i]!=0)){
			cout<<h[i]<<" ";
			s[k]=h[i];
			k++;
			i++;
		}
		else if(h[i]!=0){
			cout<<h[i]<<" ";
			
		}
		i++;
	}sort(s,s+k);
	cout<<endl;
	for(i=0;i<k;i++)
	cout<<s[i]<<" ";
	return 0;
}
/**************************************************************
	Problem: 1471
	User: houshanglin
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2096 kb
****************************************************************/