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.
# < 10 = 9 * 1
# < 100 = 90 * 2
# < 1000 = 900 * 3
# < 10000 = 9000 * 4
# ...

n = int(input())
res = 0
current = 1
step = 0

while True:
    current *= 9
    step += 1
    
    if n <= current:
        res += n * step
        break

    res += current * step
    n -= current

print(res)