def fib_gen():
	yield 1
	yield 1

	a = [1,1]
	c = 3

	while True:
		val = a[0] + a[1]
		yield val
		a[1] = a[0]
		a[0] = val

gen = fib_gen()
cnt = 0

while True:
	cnt += 1
	val = gen.next()

	if len(str(val)) == 1000:
		print cnt
		break