模拟队列

import java.util.Scanner;
import java.io.BufferedInputStream;

class Main {
    static int[] save = new int[100010];

    public static void main(String[] args) {
        Scanner sc = new Scanner(new BufferedInputStream(System.in));
        int len = sc.nextInt(), start = 0, end = -1;
        sc.nextLine();
        while (len-- > 0) {
            String cmd = sc.nextLine();
            switch (cmd.charAt(0)) {
                case 'e'://Empty?
                    System.out.println(end < start ? "YES" : "NO");
                    break;
                case 'q':
                    System.out.println(save[start]);
                    break;
                case 'p':
                    if (cmd.charAt(1) == 'u')//PUSH
                        save[++end] = Integer.parseInt(cmd.substring(5, cmd.length()));
                    else//POP
                        start++;
                    break;
            }
        }
    }
}