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 log10 

N = 13
digits = 0 
res = 0 

length = round(log10(N)) 
while length: 
    digits = N - pow(10, length) + 1 
    digits *= (length + 1) 
    res += digits 
    N = pow(10, length) - 1
    length -= 1  


print(res + 9) 
