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

int main() {
    string s;
    cin >> s;
    int n = s.length();
    for (int i = 0; i < n / 2; i++) {
        if (s[i] != s[n - 1 - i]) {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}

输入字符串为 “abba” 时，输出为 “Yes”。（    ）