# include <bits/stdc++.h>

using namespace std;
string s;int l,r;
int main(){
	cin>>s;
	l=0,r=s.size()-1;
	while(l<=r){
		if(s[l]!=s[r]){
			cout<<"no";
			return 0;
		}
		l++,r--; 
	}
	cout<<"yes";
	return 0;
}