#include <bits/stdc++.h> using namespace std; using ll= long long; using ull=unsigned long long; using ldo =long double; #define rep(i,n,k) for(ll i = k; i < (ll)(n); i++) template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; } template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; } const ll INF = 1e18; struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star; 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; }