Ugly Number

/**
 * This program inputs a number and checks whether the number entered is an ugly number or not.
 * For more information, please visit: https://goo.gl/vkv3Rv
 */
import java.util.*;
public class Ugly_Number
{
    static boolean isPrime(int num) //Function to check whether a number is prime or not.
    {
        int i,flag=1;
        if(num == 2)
            return true;
        else
        {
        for(i=2;i<num;i++)
        {
            if(num%i == 0)
            {
                flag = 0;
                break;
            }
        }
        if(flag == 1)
            return true;
        else
            return false;
        }
    }

    static ArrayList<Integer> findPrimeFactors(int num) //Function to return all the prime factors of a number.
    {
        ArrayList<Integer> list = new ArrayList<Integer>();
        int i;
        for(i=2;i<=num;i++)
        {
            if(num%i == 0 && isPrime(i))
            {
                list.add(i);
            }
        }

        return list;
    }

    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Please enter a number.");
        int num = sc.nextInt();
        ArrayList<Integer> list = findPrimeFactors(num);
        if(num == 1) //1 is an ugly number by convention.
        {
            System.out.println(num+" is an ugly number.");
        }
        else
        {
            int i,flag=1;
            for(i=0;i<list.size();i++)
            {
                if(list.get(i) > 5) //Checking whether the number has any prime factors except 2, 3 and 5.
                {
                    flag = 0;
                    break;
                }
            }

            if(flag == 1)
                System.out.println(num+" is an ugly number.");
            else
                System.out.println(num+" is not an ugly number.");
        }
        sc.close();
    }
}