Problem Statement

When Takahashi writes an integer, he uses a comma every third digit from the right. For example, $1234567$ is written as 1,234,567, and $777$ is written as 777.

How many commas will be used in total when he writes each integer from $1$ through $N$ once?

Constraints

• $1 \leq N \leq 10^{15}$
• $N$ is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the total number of commas.