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.
# BY hassan alkanash
import math

ans=0
k=1
i = 9
n = int(input())
while (n >= i):

    n -= i
    ans += i * k
    k+=1
    i = i * 10
ans += n * k
print(ans)