合法IP

package com.exam.hw;

import java.util.Scanner;


public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
	
		Scanner scan =new Scanner(System.in);
		System.out.println(legalIp(scan.nextLine()));
	}

	public static String legalIp(String ip) {
		// TODO Auto-generated method stub
		ip=ip.trim();
	if(ip.matches("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}")){
		String[] ipArr=ip.split("\\.");
		int ip1=Integer.parseInt(ipArr[0]);
		int ip2=Integer.parseInt(ipArr[1]);
		int ip3=Integer.parseInt(ipArr[2]);
		int ip4=Integer.parseInt(ipArr[3]);
		if(ip1<=0 || ip1>=224 ||ip1==127 || ip2<0 || ip2>255 || 
		   ip3<0 || ip3>255 || ip4<0 || ip4>255  )
			return "NO";
		if(ip1>=1&&ip1<=126){
			if(ip2==ip3&&ip3==ip4){
				if(ip2==0||ip2==255)
					return "NO";
				else
					return "YES";
			}
			else{
				return "YES";
			}
		}else if(ip1>=128 && ip1<=191){
			if(ip3==ip4){
				if(ip3==0 || ip3==255)
					return "NO";
				else
					return "YES";
			}else{
				return "YES";
			}
		}else{
			if(ip4==0||ip4==255)
				return "NO";
			else
				return "YES";
		}
	}
	else
     return"NO"; 
}
	
}