#include<bits/stdc++.h>
using namespace std;
int main(){
    string s;
    cin>>s;
    int len = s.size();
    for(int i=0,j=len-1;i<=len/2;i++,j--){
        if(s[i]!=s[j]){
            cout<<"no"<<endl;
			return 0; 
        }
    }
    cout<<"yes"<<endl;
    return 0;
}