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.
n=int(input())
c=0
t=9
i=0
p=0
l=0
while c<n:
    i+=1
    c=c+t*i
    if c>=n:
        break
    p+=t
    l=c
    t=t*10
print(l+(n-p)*i)