#!/usr/bin/python

	n = raw_input('n = ')

	n = int(n)

	if n % 3 == 1:
		print "f(n) = %d" % (3**(n//3-1) * 2**2)
	elif n % 3 == 2:
		print "f(n) = %d" % (3**(n//3) * 2)
	else:
		print "f(n) = %d" % (3**(n//3))

	#print "%d" % (n % 3)