text: #include<iostream>
  #include<algorithm>
  #include<cmath>
  #include<vector>
  #include<map>
  #include<queue>
  #define rep(i, n) for (int i = 0; i < (n); ++i)
  #define rep1(i, n) for (int i = 1; i < (n); ++i)
  using namespace std;
  using ll = long long;
  using P = pair<int, int>;
  const int INF = 1001001001;
  
  int main() {
    char S[3];
    cin >> S;
  
    char c = S[0];
    string ans;
    if (c == S[1] && c == S[2]) ans = "No";
    else ans = "Yes";
    cout << ans << endl;
    return 0;
  }
  