Problem:
Score : 200 points

Problem Statement

Given is an integer N. Find the number of positive integers less than or equal to N that have an odd number of digits (in base ten without leading zeros).

Constraints

1 \leq N \leq 10^5

Input

Input is given from Standard Input in the following format:

N

Output

Print the number of positive integers less than or equal to N that have an odd number of digits.

Sample Input 1

11

Sample Output 1

9

Among the positive integers less than or equal to 11, nine integers have an odd number of digits: 1, 2, \ldots, 9.

Sample Input 2

136

Sample Output 2

46

In addition to 1, 2, \ldots, 9, another 37 integers also have an odd number of digits: 100, 101, \ldots, 136.

Sample Input 3

100000

Sample Output 3

90909

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
 
class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        
        if(1 <= n || n <= 9) {
        	System.out.println(n);
        } else if(10 <= n || n <= 99) {
        	System.out.println(9);
        } else if(100 <= n || n <= 999) {
        	System.out.println(9 + n - 99);
        } else if(1000 <= n || n <= 9999) {
        	System.out.println(909);
        } else if(10000 <= n || n <= 99999) {
        	System.out.println(909 + n - 9999);
        } else {
        	System.out.println(90909);
        }
        
        
        sc.close();
    }
}