#include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define rep(i, n) for (int i = 0; i < n; i++)
#define INF (1LL << 60)
#define all(v) (v).begin(), (v).end()

template <class T>
void chmin(T &a, T b) {
    if (a > b) a = b;
}

template <class T>
void chmax(T &a, T b) {
    if (a < b) a = b;
}

int main() {
    string S;
    cin >> S;
    if (S[0] == S[1])
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
}