#include <iostream>
#include <string>
using namespace std;

int main()
{
 string str;
 while (cin>>str){
 int a=str.size(),r=1;
 for(int i=1;i<=a/2;i++)
 if(str[i-1]!=str[a-i]){
 r=0;
 break;
 }
 if(r==0)
 cout<<"no"<<endl;
 else
 cout<<"yes"<<endl;
 }
 return 0;
}