def get_fraction(c):
	(n, d) = (1, 2)
	for i in xrange(1, c):
		(n, d) = (2*d+n, d) # add 2
		(n, d) = (d, n) # 1/x, swap entries
	return (d+n, d) # add 1

count = 0
for i in xrange(1, 1000):
	(n, d) = get_fraction(i)
	if len(str(n)) > len(str(d)):
		count += 1

print count