// 2019 IUSB Programming Competition
// Round 1 Problem 2
// Check if a string is a palindrome
// Solution by Liguo Yu

#include <iostream>
#include <string>
using namespace std;

int main()
{
	bool yes = true;
	string word;
	getline(cin, word);
	
	for(int i = 0; i < word.length(); i++)
		word[i] = tolower(word[i]);
 
	int size = 0;
	
	for(int i = 0; i < word.length(); i++)
	{
		if ((int)word[i] >= 97 && (int)word[i] <= 122)
		{
			size ++;
		}
	}
	
	int * a = new int[size];
	
	int j = 0;
	
	for(int i = 0; i < word.length(); i++)
	{
		if ((int)word[i] >= 97 && (int)word[i] <= 122)
		{
			a[j] =word[i];
			j = j+ 1;
		}
	}

	for(int i = size - 1; i >= 0; i--)
	{
		if (a[i] != a[size - i - 1])
		{
			yes = false;
		}
	}
	
	if(yes == true)  cout << "yes";
	else cout << "no";

	return 0;
}