#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main(){
    string word1,word2;
    cin>>word1;
    word2=word1;
    reverse(word1.begin(),word1.end());
    if(word1==word2)
    {
        cout<<"YES";
    }
    else
    {
        cout<<"Invalid input";
        return 0;
    }
    else
    {
        cout<<"NO";
    }
}