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

int main() {
	set<int> S = {1,2,3,4,5,6,0};
	for(auto it = S.begin(); it!=S.end(); /* don't do anything here*/ ) {
		if(*it % 2 == 0) it = S.erase(it);
		else {
			cout<<*it<<endl;
			it++;			
		}
	}
	return 0;
}