#include <iostream #include <string using namespace std;

int main() { string s; getline(cin, s); // 读取整行，包含空格

int left = 0;
int right = s.length() - 1;
bool isPal = true;

while (left < right) {
    if (s[left] != s[right]) {
        isPal = false;
        break;
    }
    left++;
    right--;
}

cout << (isPal ? "yes" : "no") << endl;
return 0;

}