Vanya got an important task — he should enumerate books in the library and label each book with its number. Each of the *n* books should be assigned with a number from 1 to *n*. Naturally, distinct books should be assigned distinct numbers.

Vanya wants to know how many digits he will have to write down as he labels the books.
The first line contains integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">9</sup>) — the number of books in the library.
from math import log

n = int(input())

t = int(log(8*n+1,9))-1

i = 0
ans = 0
while i <= t:
	ans = ans + 9*i
	i = i + 1

r = n - (9**(t+1)-9)//8

print(ans + r*(t+1))