import java.util.Scanner; import java.util.ArrayList; public class PrimeFactors { public static ArrayList Factors(int num){ ArrayList factors = new ArrayList<>(); if (num <= 1){ System.out.println("no prime factor!."); } while (num%2 == 0){ factors.add(2); num /= 2; } for(int i = 3; i*i <= num; i+=2){ while (num%i == 0){ factors.add(i); num /= i; } } if (num > 1 ){ factors.add(num); } return factors; } public static void main(String[] args){ Scanner sc = new Scanner(System.in); int number = sc.nextInt(); ArrayList factors = Factors(number); if (!factors.isEmpty()){ System.out.println("factors = "+ factors); } } }