#include<iostream>
#include<string.h>
using namespace std;
int main(){
char a[1000];
cin >> a ;
int count = 0;
for(int i = 0; i < strlen(a)/2 ;i++){
if(a[i] == a[strlen(a)-1-i]){
count ++;
}
}
(count > 0) ? cout << "yes" : cout << "no";
return 0 ;
}