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.
import math
import string


def main_function():
    n = int(input())
    counter = 0
    number_of_digits = 1
    starter = 9
    while n > 0:
        if n > starter:
            counter += number_of_digits * starter
            n -= starter
            number_of_digits += 1
            starter = starter * 10 + starter
        else:
            counter += number_of_digits * n
            n -= n
    print(counter)



main_function()

