from re import *

regles = { "a": "bc",
		"b": "a",
		"c": "aaa"
		}
ruban = "a"*65

while ruban != "a":
	if not ("b" in ruban or "c" in ruban):
		print len(ruban)
	ruban += regles[ruban[:1]]
	ruban = ruban[2:]