#include <iostream>

#include <string> 

#include <sstream>

using namespace std;

int main()

{

string x;

while (cin >> x)

{

bool n = true;

for (int i = 0; i < x.length()/2; i++)

{

if (x[i] != x[x.length() - 1 - i])

{

n = false;

break;

}

}

cout << (n ? "yes" : "no") << endl;

}

}