#include<iostream>
#include<string>

using namespace std;

int main(){
string input;
bool recursive;
while(!cin.eof()){
recursive = true;
getline(cin,input);
for(int i=0;i<=input.length()/2;i++){
if(input[i]!=input[input.length()-i-1]){
recursive = false;
break;
}
}
if(recursive)
cout<<"yes\n";
else
cout<<"no\n";
}
return 0;
}

為什麼一直說"請勿輸出題目未要求的文字: "

明明輸出就是yes