Palindrome quiz

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 

public class TaskK
{
  public static void main(String[] args)
  {
    FastReader reader = new FastReader();
    String input_string = reader.nextLine();
    char[] input = input_string.toCharArray();
    char[] cleared = new char[input.length];
    int index = 0;
    for (int i = 0;i < input.length;i++) 
    {
      if(Character.isLetter(input[i]))
      {
         cleared[index] = Character.toLowerCase(input[i]);
         index++;
      }
    } 
    for(int i = 0; i < index; i++)
    {
      if (cleared[i] != cleared[index-i-1])
       {
        System.out.print("NO");
        return;
      } 
    }
    System.out.print("YES");
  }
}
  
class FastReader
{ 
  BufferedReader br; 
  StringTokenizer st; 
  
  public FastReader() 
  { 
    br = new BufferedReader(new
    InputStreamReader(System.in)); 
  } 
  
  String next() 
  { 
    while (st == null || !st.hasMoreElements()) 
    { 
      try
      { 
        st = new StringTokenizer(br.readLine()); 
      } 
      catch (IOException  e) 
      { 
        e.printStackTrace(); 
      } 
    } 
    return st.nextToken(); 
  } 
  
  public int nextInt() 
  { 
    return Integer.parseInt(next()); 
  } 
  
  long nextLong() 
  { 
    return Long.parseLong(next()); 
  } 
  
  double nextDouble() 
  { 
    return Double.parseDouble(next()); 
  } 
  
  String nextLine() 
  { 
    String str = ""; 
    try
    { 
      str = br.readLine(); 
    } 
    catch (IOException e) 
    { 
      e.printStackTrace(); 
    } 
    return str; 
  } 
} 
  

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED