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 digits(N):
    if N<10:
        return 1
    else:
        return digits(N//10)+1
def power(x,n):
    if n==0:
        return 1
    elif n%2==0:
        return power(x*x,n//2)
    else:
        return x*power(x*x,n//2)
def ans(n):
    if n<10:
        return n
    else:
        d=digits(n)
        num=power(10,d-1)
        return ans(num-1)+(n-num+1)*d
n=int(input())
print(ans(n))