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=input()
S=len(n)
k=0
p=1
kr=0
z=10
while int(n)>0 :
    k=k+p
    kr=kr+1
    n=int(n)-1
    if (kr+1)%z==0 and kr!=0 :
        z=z*10
        p=p+1
    
print(k)
    
    
