Numbers

Let's define the sum of digits of a numerical sequence as the total sum of the digits of all numbers within that sequence. For instance, consider the sequence of numbers 14, 22, 239. The sum of digits is calculated as (1 + 4) + (2 + 2) + (2 + 3 + 9) = 23.

Your task is to determine the sum of digits for the following numerical sequence given a specific n:

1, 2, 3, ..., 10^n-1

Input

The input consists of a single line containing an integer n (1 ≤ n ≤ 100000).

Output

Output a single number, which is the sum of digits of the specified numerical sequence.

Examples