#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    string S;
    cin >> S;

    if(S[0] == S[1] && S[0] != S[2]){
        cout << "Yes" << endl;
    }else{
        cout << "No" << endl;
    }

    return 0;
}