#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    string s;
    cin >> s;
    bool flag = false;
    if(s[0] == s[1]){
        flag = true;
    }
    if(s[1] == s[2]){
        flag = false;
    }
    if(flag){
        cout << "Yes" << endl;
    }else{
        cout << "No" << endl;
    }
}