#include <iostream>

using namespace std;

string arr;

int num, numd;

int main(){

getline(cin,arr);

num = arr.size();

numd = arr.size()/2;

for(int i=0; i<=numd-1; i++){

if(arr[i]== arr[num-i-1]){

cout<<"yes\n";

break;

}

else{

cout<<"no\n";

break;

}

}

if(arr.size()==1){

cout<<"yes\n";

}

return 0;

}