#include <iostream>
#include <sstream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <list>
#include <queue>
#include <deque>
//#include <map>
#include <set>
#include <stack>
#include <cstring>
#define MAX_SIZE 100
#define INF 0x7fffffff
using namespace std;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
int reverse(int x) {
int rev = 0;
while(x != 0){
rev = rev*10 + x%10;
x = x/10;
}
return rev;
}
int main() {
int n; cin >> n;
if (n == reverse(n)) {
cout << "Ok" << "\n";
} else {
cout << "No" << "\n";
}
return 0;
}