#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 ;

}

if(a[i] == a[strlen(a)-1-i]){

==改成!=，然後下面輸出的yes跟no互換