def conjugate(verb):
	if verb[-2:] == 'ed' and verb[-3] not in {'a', 'e', 'i', 'o', 'u'}:
		verb = verb[:-2]
	if verb[-1] in {'a', 'i', 'o', 'u'}:
		verb = verb + 'es'
	elif verb[-1] != 'e' and (verb[-1] in {'s', 'x'} or verb[-2] in {'s', 'x'} or verb[-2:] == 'ch'):
		verb = verb + 'es'
	elif verb[-1] == 'y' and verb[-2] not in {'a', 'e', 'i', 'o', 'u'}:
		verb = verb[:-1] + 'ies'
	else:
		verb = verb + 's'

	return verb