include

include

using namespace std;

int main() {

list<int> LA, LB;
int num;

while (cin >> num && num != -1) {
	LA.push_back(num);
}
while (cin >> num && num != -1) {
	LB.push_back(num);
}
list<int>::iterator itA = LA.begin(), itB = LB.begin(), itC;
list<int> LC;
while (itA != LA.end() && itB != LB.end()) {
	if (*itA < *itB) {
		LC.push_back(*itA);
		++itA;
	} else {
		LC.push_back(*itB);
		++itB;
	}
}
while (itA != LA.end()) {
	LC.push_back(*itA);
	++itA;
}
while (itB != LB.end()) {
	LC.push_back(*itB);
	++itB;
}
for (const int &val : LC) {
	cout << val << " ";
}
cout << endl;

return 0;

}