# include<stdio.h>
# include<algorithm>
# include<set>
using namespace std;
int main(){
int n,m,num;
set<int>s;
while(scanf("%d %d",&n,&m)!=EOF){
s.clear();
for(int i=0;i<n;i++){
scanf("%d",&num);
s.insert(num);
}
for(int i=0;i<m;i++){
scanf("%d",&num);
s.insert(num);
}
set<int>::iterator it;
for(it=s.begin();it!=s.end();it++){
if(it==s.begin()){
printf("%d",*it);
}
else{
printf(" %d",*it);
}
}
printf("\n");
}
return 0;
}