#include <iostream>
#include <string>

using namespace std;

#define i64 int_fast64_t
const i64 INF = INT64_MAX;
const i64 ERR = INT64_MIN;
const i64 MOD = 998244353;

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;
  }
}