#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const double pi = 3.14159265359879323846264338327950288419;
const int INF = 2147483647;
using p = pair<int, int>;

int main() {
    string s;
    cin >> s;
    if (s[0] == s[1] and s[1] != s[2]) { cout << "Yes" << endl; }
    else { cout << "No" << endl; }
    return 0;
}