//MMA Contest 015 A
#include<bits/stdc++.h>
using namespace std;
typedef int64_t ll;

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;
  
  return 0;
}