显示某个月的天数

import java.util.Scanner;
public class Days {
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);
        int day = 0;
        System.out.println("请输入年份：");
        int year = input.nextInt();
        System.out.println("请输入月份：");
        int month = input.nextInt();
        if (0 < month && month < 12){
            if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12){
                day = 31;
            }
            else if (month == 4 || month == 6 || month == 9 || month == 11){
                day = 30;
            }
            else {
                if (year % 4 == 0 && year % 100 != 0 || year % 400 ==0){
                    day = 29;
                }
                else{
                    day = 28;
                }
            }
            System.out.println(year + "年 " +month + "月有" + day + "天");
        }
        else{
            System.out.println("请输入1-12");
        }
        
        
    }
}