#include <iostream>
#include <list>
using namespace std;

int main() {
	// your code goes here
	list<int> l;
	l.push_back(1);
	l.push_back(2);
	
	l.insert(l.end(), l.begin(), l.end());
	
	for(list<int>::const_iterator it = l.begin();
		it != l.end(); ++it)
		{
			cout << *it;
		}
	return 0;
}