#include <bits/stdc++.h>
using ll = long long;
using namespace std;
#define rep(i, a, b) for (ll i = a; i < ll(b); ++i)

int main() {
    string s;
    cin >> s;
    if (s[0] == s[1]) {
        cout << "Yes" << endl;
        return 0;
    }

    cout << "No" << endl;
}