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.
amount = int(input())#[::-1]
answer = 0
current = 1
while(amount - current>=0):
    answer += (amount - current + 1)
    current *= 10
print(answer)
    
