#include <iostream>
using namespace std;
bool huiwen(const char*str,int strLen){
if(strLen<=1)
return true;
if(str[0]==str[strLen-1])
{
return huiwen(str+1,strLen-2);
}
return false;
}
int main() {
char str[]="aaaabaaaa";
int flag=huiwen(str,9);
if(flag)
cout<<str<<"is a palindrome."<<endl;
else
cout<<str<<"is not a palindrome."<<endl;
return 0;
}