#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using tp3 = tuple<int, int, int>;
using Mat = vector<vector<ll>>;
constexpr int INF = 1 << 28;
constexpr ll INFL = 1ll << 60;
constexpr int dh[4] = { 0,1,0,-1 };
constexpr int dw[4] = { -1,0,1,0 };
bool isin(const int H, const int W, const int h, const int w) {
    return 0 <= h && h < H && 0 <= w && w < W;
}
template<typename T>
T minch(T& l, T r) {
    return l = min(l, r);
}
template<typename T>
T maxch(T& l, T r) {
    return l = max(l, r);
}
template<typename T>
void output(const T& val) {
    cout << val << endl;
}
template<typename T>
void output(const vector<T>& vec, const bool newline = false) {
    for (const T& val : vec)cout << val << (newline ? '\n' : ' '); cout << endl;
}
template<typename T>
void output(const vector<vector<T>>& mat) {
    for (const auto& row : mat)output(row);
}
// ============ template finished ============

string erasing(string s, vector<bool> erase) {
    const int N = s.size();
    set<char> st;
    rep(i, N)if (erase[i]) {
        st.insert(s[i]);
        s[i] = ' ';
    }
    for (char& c : s)if (st.find(c) != st.end())c = ' ';
    return s;
}

bool judge(string s) {
    for (char c : s)if (c != ' ')return true;
    return false;
}

int main()
{
    string s;
    getline(cin, s);
    int N = s.size();
    rep(r, N + 1)rep(l, r - 1) {
        vector<bool> erase(N, false);
        rep(i, l)erase[i] = true;
        REP(i, l, r)if ((i - l) % 2 == 1)erase[i] = true;
        REP(i, r, N)erase[i] = true;

        auto parsed = erasing(s, erase);
        if (judge(parsed)) {
            output("Yes");
            return 0;
        }
    }
    output("NO");
    return 0;
}