Maximum Element

package stacksAndQueues;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.Deque;

public class MaximumElements {
    public static void main(String[] args) throws IOException {
        BufferedReader scanner = new BufferedReader(new InputStreamReader(System.in));
        ArrayDeque<Integer> stack = new ArrayDeque<>();
        int n = Integer.parseInt(scanner.readLine());
        int maxElement = Integer.MIN_VALUE;
        StringBuilder sb = new StringBuilder(n);
        for (int i = 0; i <n; i++) {
            String[] input = scanner.readLine().split(" ");
            switch (input[0]) {
                case "1":
                    int el = Integer.parseInt(input[1]);
                    stack.push(el);
                    if (maxElement < el) maxElement = el;
                    break;
                case "2":
                   el = stack.pop();
                   if (el == maxElement) maxElement = maxEl(stack);
                    break;
                case "3":
                    sb.append(maxElement).append(System.lineSeparator());
                    break;
            }
        }
        System.out.println(sb.toString());
    }
    static int maxEl(Deque<Integer> stack) {
        int bestInt = Integer.MIN_VALUE;
        for (Integer integer : stack) {
            if (integer>bestInt){
                bestInt = integer;
            }
        }
        return bestInt;
    }
}