source_code: 
  import java.util.Scanner;
  
  public class BDigitSequence {
      public static void main(String[] args) {
          Scanner scan = new Scanner(System.in);
          long k = scan.nextLong();
  
          long digits = 1;
          long counter = 9L;
  
          while(k > counter * digits) {
              k -= counter * digits;
              counter *= 10;
              digits++;
          }
  
          long num = (long)(Math.ceil((double)k/digits));
          String s = String.valueOf((long)Math.pow(10,digits-1) - 1 + num );
  
          System.out.println(s.charAt((int)((k+digits-1)%digits)));
      }
  }
  