public class PermutationSeating {

    public static void main (String[] argv)
    {
	int numSeats = 3;    // M
	int numPeople = 2;   // K

	int n = countPermutations (numSeats, numPeople);

	System.out.println (numPeople + " can sit on " + numSeats + " seats in " + n + " different arrangements");
    }

    static int countPermutations (int numSpaces, int numRemaining)
    {
        // Given numRemaining to assign among numSpaces seats, 
        // count all possible arrangements.

        // Bottom out case: if none are remaining, there's only one way to do that.
	if (numRemaining == 0) {
	    return 1;
	}

        // Otherwise, obtain the count for a smaller version of the problem.
	int n = countPermutations (numSpaces-1, numRemaining-1);

        // Since one person can chose from among numSpaces, there
        // numSpaces ways of doing that, which we multiply with n.
	return (numSpaces * n);
    }

}