#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
  // input
  string S;
  cin >> S;
  int total = 0;
  string ans="No";
  if(S[0] == S[1] && S[1] != S[2]){
    ans = "Yes";
  }


  cout << ans << endl;
  // output 
}