#include <iostream>
#include <cmath>
#include <iostream>
#include <iterator>
#include <map>
#include <set>
#include <string>
#include <vector>
#include <algorithm>
#include <stack>
#include <deque>
#include <queue>
#include <climits>


#define int long long
#define db double
#define ff first
#define ss second

using namespace std;

const int MOD = 1e9 + 7;
// const int INF = LONG_MAX;
const int INF = INT_MAX;
const int K = 31;

int hash_substring(vector<int>& h, vector<int>& k, int l, int r, int n) {
    return (h[r] - h[l]) * k[n - l] % MOD;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    string s;
    cin >> s;
    vector<int> hash1(s.size());
    vector<int> hash2(s.size());
    vector<int> k(s.size() + 1);
    k[0] = 1;
    for (int i = 1; i < s.size() + 1; i++) {
        k[i] = k[0] * K;
    }
    int h = 0;
    for (int i = 0; i < s.size(); i++) {
        int x = s[i] - 'a' + 1;
        h = (h * K + x) % MOD;
        hash1[i] = h;
    }
    h = 0;
    for (int i = s.size() - 1; i >= 0; i--) {
        int x = s[i] - 'a' + 1;
        h = (h * K + x) % MOD;
        hash2[s.size() - 1 - i] = h;
    }
    int h1 = 0, h2 = 0;
    int l = 0, r = 1;
    h1 = hash_substring(hash1, k, l, r, s.size());
    h2 = hash_substring(hash2, k, s.size() - 1 - r, s.size() - 1 - l, s.size());
    if (h1 == h2) {
        cout << "YES";
    }
    else {
        cout << "NO";
    }
}
// a              ka + a   k^2a + ka + a
// k^2a + ka + a  ka + a   a

// aaa