// I SELL YOU...! 
#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
#include<queue>
#include<chrono>
#include<iomanip>
#include<map>
#include<set>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
using TP = tuple<ll,ll,ll>;
void init_io(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
}
signed main(){
  init_io();
  string s;
  cin >> s;
  if (s[0] == s[1] && s[0] != s[2]) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}