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


int main() {

	set<int> s;
	for (int i = 0; i < 10; i++) {
		s.insert(i);
	}

	for (auto it = s.begin(); it != s.end();it++) {

		if ((*it) % 2 == 0)
			s.erase(it);
	}



	for (auto it = s.begin(); it != s.end();) {

		if ((*it) % 2 == 0)
			it = s.erase(it);
		else
			it++;

	}

}