#include <iostream>
using namespace std;

bool isPalindrome(const string &s) {
    int left = 0, right = s.length() - 1;

    while (left < right) {
        if (s[left] != s[right])
            return false;
        left++;
        right--;
    }

    return true;
}

int main() {
    string S;
    cin >> S;

    if (isPalindrome(S))
        cout << "YES" << endl;
    else
        cout << "NO" << endl;

    return 0;
}