NEXT CODE IS NOT AC SOLUTION
but it a way to test your Solution


next class run with command: "java tester >test.txt"
then you can run your solution and compare your answers with this tester's
But you cant test some tests where n>30000, therefore
try to think and about it.
Good luck to TEST, I AC))
////////////////////////tester.java///////////////////////////
import java.io.*;
import java.util.*;

public class tester{
 public static void main(String[] args){
  int s=0,ts=0;
  int t;
  int a[]=new int[30000];
  for(int i=0;i<30000;i++){
   a[i]=0;
  }
  for(int i=1;i<=50000;i++){
   ts=s;
   t=i;
   while(t>=10){
    if(t%10==1){
     s++;
    }
    t/=10;
   }
   if(t==1){
    s++;

   }
   if(ts!=s)
    a[s-1]=i;
  }

  for(int i=0;i<30000;i++){
   if(a[i]!=0)
    System.out.println((i+1) + " "+ a[i]);
   else
    System.out.println((i+1)+ " " +"Petr lies");
  }
 }
}

////////////////////////end///////////////////////////