[groom] Stack

package kr.co.doo.cote.groom;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Stack;
import java.util.StringTokenizer;

public class Stackk {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        int end = Integer.parseInt(st.nextToken());
        int sSize = Integer.parseInt(st.nextToken());
        Stack<String> stack = new Stack<>();

        for (int i = 0; i < end; i++) {
            StringTokenizer stringTokenizer = new StringTokenizer(br.readLine());
            String cmd = stringTokenizer.nextToken();
            String num = "";
            if (stringTokenizer.hasMoreTokens()) {
                num = stringTokenizer.nextToken();
            }

            if (stack.size() == 0 && cmd.equals("pop")) {
                System.out.println("Underflow");
            } else if (cmd.equals("pop")) {
                System.out.println(stack.pop());
            }
            if (stack.size() >= sSize && cmd.equals("push")) {
                System.out.println("Overflow");
            } else if (cmd.equals("push")) {
                stack.push(num);
            }
        }
    }
}