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.
def f(n,m):
    if n >= 10**(m+1):
        return (10**(m+1)-(10**m))*(m+1) + f(n,m+1)
    elif n >= 10**m:
        if m==0:
            return n
        else:
            return (n - 10**(m) +1)*(m+1)
    else:
        return 0
print(f(int(input()),0))
