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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

"use strict";
const Main = (input) =>{
   let xs = input.trim().split('');
   let xs1 = input.trim().split(' '); 
   if(xs.length == 1){
   console.log(xs1[0]);
   }else if(xs.length == 2){
   console.log(9);
   }else if(xs.length == 3){
   console.log(xs1[0]-99 + 9);
   }else if(xs.length == 4){
   console.log(909);
   }else if(xs.length == 5){
   console.log(xs1[0]-9999 + 999);
   }else if(xs.length == 6){
   console.log(90909);
   }      
}
Main(require('fs').readFileSync('/dev/stdin','utf8'));