n = input()

l = str(n)

if len(l) == 1:
	a = 9
	b = 10 * 2 - 1
	print(a + b)
elif len(l) % 2 != 0:
	a = 9
	b = 10 * len(l) // 2 + 1
	print(a + b)
else:
	a = 9
	b = 10 * len(l) // 2
	print(a + b)