Solution.java

import java.util.Scanner;

class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            String IP = in.next();
            System.out.println(IP.matches(new MyRegex().pattern));
        }
    }
}

class MyRegex {
    String ipPart = "([01]?\\d{1,2}|2[0-4]\\d|25[0-5])";
    String pattern = "(" + ipPart + "\\.){3}" + ipPart;
}