#include<iostream>
#include<ctype.h>
using namespace std;
int main() {
string s; cin >> s;
int a = 0;
for(int i = 0; i < (s.length() / 2); i++)
if(s[i] == s[s.length() - 1 - i]) a++;
if(a == (s.length() / 2)) cout << "YES";
else cout << "NO";
return 0;
}