#include <bits/stdc++.h>
using namespace std;
constexpr int MOD = 998244353;
constexpr int MD = 1000000007;
constexpr int INF = INT_MAX;
constexpr long long LINF = LLONG_MAX;
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
using ll = long long;using vi = vector<int>;using vll = vector<ll>;
template <class T>
using ps = pair<T, T>;
template <class T>
using vec = vector<T>;
template <class T>
using pqg = priority_queue<T, vector<T>, greater<T>>;  // ascendent

template <typename T>
int sz(const T& x) { return x.size(); }

// a = min(a,b)
template <typename T, typename S>
inline bool chmin(T& a, const S& b) {
  return (a > b ? a = b, 1 : 0);
}
template <typename T, typename S>
inline bool chmax(T& a, const S& b) {
  return (a < b ? a = b, 1 : 0);
}

ll mpow(int base, int exponent, int mod){
    if(exponent == 0) return 1;
    ll c = mpow(base, exponent/2, mod);
    c *= c;
    c %= mod;
    if(exponent % 2 == 1){
        c *= base;
        c %= mod;
    }
    return c;
}

/* 
auto push = [&](int r, int c){
    if(r < 0 || c < 0 || r >= h || c >= w) return;
    if(dist[r][c] != -1) return;
};
*/ //dfs/bfs埋め込み用

/*
class edge{
public:
    int to, weight;
    edge(int a, int b){
        to = a; weight = b;
    }
};
*/ //template of edge
/*class edge2{
public:
    int from, to, weight;
    edge2(int w, int a, int b){
        from = w; to = a; weight = b;
    }
};
bool comp(edge2 a, edge2 b){
    return a.weight < b.weight;
}
*/ //template of edge2
struct before_main_function {
  before_main_function() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << setprecision(20) << fixed;
#define endl "\n"
  }
} before_main_function;
int main(int /*argc*/, char** /*argv*/){
  string s;
  cin >> s;
  if(s[0] == s[1] && s[1] != s[2]) cout << "Yes\n";
  else cout << "No\n";
  return 0;
}