stack_Maximum Element

import java.util.ArrayDeque;
import java.util.Scanner;

public class stack_Maximum_Element {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int num = scanner.nextInt();

        ArrayDeque<Integer> stack = new ArrayDeque<>();

        for (int i = 0; i < num; i++) {
            int command = scanner.nextInt();
            if (command == 1) {
                stack.push(scanner.nextInt());
            } else if (command == 2) {
                if (!stack.isEmpty()){
                    stack.pop();
                }

            } else if (command == 3) {
                int max = Integer.MIN_VALUE;
                int temp = 0;
                int count = stack.size();
                if (!stack.isEmpty()){

                    while (count > 0) {

                        temp = stack.pop();

                        stack.addLast(temp);

                        count--;
                        if (temp > max) {
                            max = temp;
                        }
                    }
                    System.out.println(max);
                }
            }
        }



    }
}