#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for (int i=0;i<(int)(n);i++)

int main(){
  string s;
  cin>>s;
  if(s.at(0)==s.at(1)&&s.at(0)!=s.at(2)) cout<<"Yes"<<endl;
  else cout<<"No"<<endl;
}