include

include

include

using namespace std; int main() {

list<int>a1;
int x;
cin>>x;
while (x != -1)
{
	a1.push_back(x);
	cin>>x;
}
cin>>x;
while (x != -1)
{
	a1.push_back(x);
	cin>>x;
}
a1.sort();
for (auto k = a1.begin();k != a1.end();k++)
{
	cout << *k << " ";
}
return 0;

}