import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        ArrayDeque deque = new ArrayDeque();

        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            String name = scanner.next();
            // 初始化队列中的数据
            deque.offerLast(name);
        }
        
        //java中实现队列首尾交替打印和出队
        while(deque.size()>0){
            if(deque.size()>0){
                System.out.println(deque.getFirst());
                deque.removeFirst();
            }
            if(deque.size()>0){
                System.out.println(deque.getLast());
                deque.removeLast();
            }
        }
        // write your code here......    

    }

}