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: Accepted)


import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		 Scanner scn=new Scanner(System.in);
		 int n=scn.nextInt();
		 int digit=1,count=0;
		 for(int i=1;i<=n;i++) {
			 if(i%10==0){
				 int tmp=0,x=i;
				 while(x!=0) {
					 x=x/10;
					 tmp++;
				 }
				 digit=tmp;
			 }
			 if(digit%2!=0) {
				// System.out.println(i);
					 count++;				 
			 }
		 }
		 System.out.println(count);
	}

}