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 Java7 (OpenJDK 1.7.0) (judge verdict: Wrong Answer)



import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();

		int answer = 0;
		int max5 = 90000;
		int max3 = 900;
		int max1 = 9;

		if (n - 10000 >= 0) {
			if (n - 9999 < max5)
				answer += n - 9999;
			else
				answer += max5;

		} else if (n - 100 >= 0) {
			if (n - 99 < max3)
				answer += n - 99;
			else
				answer += max3;
		} else {
			if (n >= 10) {
				answer += max1;
			} else {
				answer += n;
			}
		}
		System.out.println(answer);

	}

}