#include <iostream>
#include <string>
#include <vector>
#include <cctype>
#include <cstdlib>
#include <fstream>
#include <sstream>
#include <list>
#include <deque>


int main()
{
        std::list<int> nums = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

        auto it = nums.begin();
        auto mid = nums.begin() + nums.size() / 2;
        while (it != mid)
                if (*it == 3)
                        nums.insert (it, 6);
        for (auto &i : nums)
                std::cout << i << std::endl;
}