Problem Background

As is well known, the ultimate goal of an OIer is to AK (All Kill) IOI (International Olympiad in Informatics).

(Image from 《深入浅出 程序设计竞赛 基础册》)

As an OIer, Xiao Z also dreams of AK IOI. However, he is still too inexperienced, and even saying I AK IOI would draw scorn from the masters.

Therefore, Xiao Z can only say |A|<|O| to encourage himself.

But the Youyou master, seeing this, was dismissive, saying: With your level, you还想 AK IOI? Forget it, since you said |A|<|O|, I'll give you a problem to solve.

Poor Xiao Z is too inexperienced to solve this problem, so he has to seek help from you—the future IOI AKer.

Problem Description

Given \( O \), find the number of integers \( A \) such that \( |A| < O \).

Since Xiao Z is too inexperienced, he doesn't even dare to say |A|<|O|, so he has to study the problem of |A|<O.

Input Format

A single line containing an integer \( O \).

Output Format

A single line containing an integer, the number of integers \( A \) that satisfy the condition.

Sample Input and Output

Sample Input #1

3

Sample Output #1

5

Sample Input #2

1145141919810

Sample Output #2

2290283839619

Sample Input #3

12345

Sample Output #3

24689

Notes

Sample 1 Explanation

The possible values for \( A \) are \(-1, 0, 1\).

Data Range and Constraints

• Subtask 1 (30 points): \( 0 \le |O| \le 2^{10}-1 \);
• Subtask 2 (60 points): \( 0 \le |O| \le 2^{31}-1 \);
• Subtask 3 (10 points): \( 0 \le |O| \le 2^{63}-1 \).

\( |O| \) denotes the absolute value of \( O \).

Hints

If you are unfamiliar with absolute values, you can understand it as:

\[ |x| = \begin{cases} x & (x > 0) \\ 0 & (x = 0) \\ -x & (x < 0) \end{cases} \]

Original idea: Meatherm

见题面 Input 部分

见题面 Output 部分