#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
using ll = int_fast64_t;
using ull = uint_fast64_t;

using mint = modint998244353;

constexpr ll INF = 1ll << 60;

template<typename T, typename D> void printelem(const T& container, const D& divide){
	for(const auto& i : container) cout << i << divide;
	cout << endl;
}
template<typename T> void printelem(const T& container) { printelem(container, ", "); }

int main(){
	//インプット
	string S;
	cin >> S;

	//アウトプット
	if(S[0] == S[1] && S[0] != S[2]) cout << "Yes\n";
	else cout << "No\n";
	
	return 0;
}