#include <bits/stdc++.h>
#define mrep(i, s, n) for (int i = (s); i < (int)(n); i++)
#define rep(i, n) mrep(i, 0, n)
using namespace std;
using ll = long long;
const int INF = int(1e+9)+1;
const ll INFL = ll(1e+18)+1;

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

    string ans = "No";
    if (s[0] == s[1]) {ans = "Yes";} 

    cout << ans << endl;
}