import java.util.Scanner;

public class Main {

    static Scanner inputScanner = new Scanner(System.in); // Static object of the Scanner class.

    public static void main(String[] args) {

        int
            minimumValue = inputScanner.nextInt(), // Input the minimum value of the range.
            maximumValue = inputScanner.nextInt(); // Input the maximum value of the range.

        String tempString = new String(); // Object of the string class for temporary storage.

        // The for loop range:

        for (int nIteration = minimumValue; nIteration <= maximumValue; nIteration++) {

            tempString = String.format("%d :", nIteration); // The number of the iteration.

            for (int nRange = 2; nRange < nIteration; nRange++) {

                if (nIteration % nRange == 0) // If the remainder of the division is zero:
                    tempString += String.format(" %d", nRange); // Adding to the string.

            }

            System.out.println(tempString); // Output.

        }

        tempString = null; // Freeing an object of the class.

    }

}