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

n = int(input())
a = 0
for i in range(0, 9):
    x = 9 * 10**i
    if n > x:
        n -= x
        a += x * 10**i
    else:
        a += n * (i + 1) 
        break
print(a)