MaximumElement-java

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be nahmed Solution. */
        Scanner sc = new Scanner(System.in);
        Stack<Integer> st = new Stack<Integer>();
        Stack<Integer> st1 = new Stack<Integer>();
        int t = sc.nextInt();
        while(t-->0){
            int s = sc.nextInt();
            if(s==1){
                int a = sc.nextInt();
                if(st.size()==0){
                st1.push(a);
                st.push(a);
                
                }
                else{
                    if(a>=st1.peek()){
                    st1.push(a);
                }
                st.push(a);
                
                }
            }
            if(s==2){
                if((int)st1.peek()==(int)st.peek())
            
                st1.pop();
            
            st.pop();
            }
            if(s==3){
                System.out.println(st1.peek());
            }
        }

    }
}