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......
}
}