import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class DanceLesson
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader keyboard = new BufferedReader(
                         new InputStreamReader(System.in));

        System.out.println("Enter number of male dancers:");
        String menString = keyboard.readLine( );
        int men = Integer.parseInt(menString);

        System.out.println("Enter number of female dancers:");
        String womenString = keyboard.readLine( );
        int women = Integer.parseInt(womenString);

        if (men == 0 && women == 0)
        {
            System.out.println("Lesson is canceled. No students.");
            System.exit(0);
        }
        else if (men == 0)
        {
            System.out.println("Lesson is canceled. No men.");
            System.exit(0);
        }
        else if (women == 0)
        {
            System.out.println("Lesson is canceled. No women.");
            System.exit(0);
        }

       // women >= 0 && men >= 0
       if (women >= men)
            System.out.println("Each man must dance with " +
                                     women/(double)men + " women.");
        else
            System.out.println("Each woman must dance with " +
                                      men/(double)women + " men.");

        System.out.println("Begin the lesson.");
    }
}