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