#include<iostream>
#include<string>
using namespace std;
int main() {
string s;
cin >> s;
int i, j;
for (i=0; i < s.length()/2; i++) {
j = s.length() - i - 1;
if (s[i] != s[j])
break;
}
if (i < s.length() / 2)
cout << 'NO';
else
cout << 'YES';
return 0;
}
想知道哪里有问题,为什么输出不是YES或NO