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

int main() {
    deque<int> dq;
    
    dq.push_back(2);
    dq.push_front(1);
    dq.push_back(3); 

    for (int i = 0; i < dq.size(); i++) {
        cout << dq[i] << " ";
    }
    
    while (!dq.empty()) {
        cout << dq.front() << " ";
        dq.pop_front();
    }

    cout << "\n";
    return 0;
}