codeforces 320A MagicNumbers program in java

MagicNumbers.java

import java.util.Scanner;

public class MagicNumbers
{
    public static void main(String[] args)
    {
        Scanner z=new Scanner(System.in);
        int n=z.nextInt();
        boolean flag=true;
        for(int i=0;i<=9;i++)
        {
            if(i!=4 && i!=1)
            {
                if(Integer.toString(n).contains(String.valueOf(i))){
                    System.out.println("NO");
                    flag=false;
                    break;
                }
            }
        }
        if(flag)
        {
            if(Integer.toString(n).replaceAll("144", "").replaceAll("14", "").replaceAll("1", "").length()!=0 || Integer.toString(n).contains("444"))
                System.out.println("NO");
            else
                System.out.println("YES");
        }
    }
}