#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using i64 = long long int;
int main() {
  string s;
  cin >> s;
  cout << (s[0] == s[1] && s[0] != s[2] ? "Yes" : "No") << "\n";
  return 0;
}