#include <iostream>
#include<bits/stdc++.h>
using namespace std;

int main() {

   string s;
   cin>>s;
   
   int i,j;
   
   i=0;
   j=s.length()-1;
   int flag=1;
   while(i!=j){
       if(s[i]==s[j]){
           i++;
           j--;

       }else{
           flag=0;
       }}
       if(flag==1){
       cout<<"yes";
   }else{
       cout<<"no";
   }
   return 0;
}