Problem: You have been given a String S. You need to find and print whether this string is a palindrome or not. If yes, print "YES" (without quotes), else print "NO" (without quotes). 

Input Format
The first and only line of input contains the String S. The String shall consist of lowercase English alphabets only.

Output Format
Print the required answer on a single line.  

Constraints
 1 ≤ |S| ≤ 100   

Note
String S consists of lowercase English Alphabets only.   

SAMPLE INPUT
aba

SAMPLE OUTPUT
YES

Solution (in PYTHON):

Solution:
def stringCompare(arg1,arg2):
    """TODO: Docstring for stringCompare.finding if one string is equal to other

    :arg1: TODO

    :arg1: TODO
    :returns: TODO

    """
    if len(arg1)==len(arg2):
        for j in range(len(arg1)):
            if arg1[j]==arg2[j]:
                if j==len(arg1)-1:
                    return True
    #if the function hasn't returned true by this stage then they are not equal
        return False 
    else:
        return False
  
def reverseString(arg1):
    """TODO: Docstring for function. to reverse a given string.

    :arg1: a string 
    :returns: return the reversed string 

    """
    string=  arg1[::-1] 
    return string
def splitMiddle(arg1):
    """TODO: Docstring for function.to split any given string to two equal halves

    :arg1: string to be split 
    :returns: two parts 

    """
    length=len(arg1)
    part1=length/2

    if length%2==1:
        length_part1=part1
        length_part2=part1+1
    else:
        length_part1=part1
        length_part2=part1

    strpart1=arg1[:length_part1]
    strpart2=arg1[length_part2:length]
    return strpart1,strpart2

def checkPallindrome(arg1):
    """a funciotn to check if a string is a pallindrome

    :arg1: is the string to be checked 
    :returns: a string  

    """
    string=arg1
    first,second=splitMiddle(string)
    if stringCompare(first,reverseString(second)):
            return "YES"
    else:
            return"NO"

string = raw_input() 
print checkPallindrome(string)