/**
* @param args
*/
public static void main(String[] args) {
int month = 0;
do{
System.out.println("Input the month");
Scanner sc = new Scanner(System.in);
month = sc.nextInt();
if(month < 1 || month > 12)
System.out.println("Error,Input again");// TODO Auto-generated method stub
}while(month > 1&&month < 13);
switch (month){
case 1:System.out.println("31");break;
case 3:System.out.println("31");break;
case 5:System.out.println("31");break;
case 7:System.out.println("31");break;
case 8:System.out.println("31");break;
case 10:System.out.println("31");break;
case 12:System.out.println("31");break;
case 2:System.out.println("28");break;
case 4:System.out.println("30");break;
case 6:System.out.println("31");break;
case 9:System.out.println("31");break;
case 11:System.out.println("31");break;
}