#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d,e,f,g;
	cin>>a;
	b=a%10;
	c=a/10%10;
	d=a/100%10;
	e=a/1000%10;
	f=b+c*10;
	g=d+e*10;
	if(f==g){
		cout<<"yes";
	}else cout<<"no";
}
/**************************************************************
	Problem: 1647
	User: toughuatao1
	Language: C++
	Result: Wrong Answer
****************************************************************/