#55577: c++解供參
#include <bits/stdc++.h>
using namespace std;
int main(){
string s;
cin>>s;
bool tmp=true;
for(int i=0;i<s.size()/2;i++){
if(s[i]!=s[s.size()-1-i]){
cout<<"no\n";
tmp=false;
break;
}
}if(tmp) cout<<"yes\n";
return 0;
}