#include <bits/stdc++.h>

using namespace std;

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  long long n;
  cin >> n;

  long long ret = 0;
  for (int i = 0; i < 50; i++) {
    long long bit = (n >> (i + 1)) << i;
    if (n & (1LL<<i))
      bit += (n & ((1LL<<i) - 1)) + 1;
    if (bit & 1)
      ret |= 1LL << i;
  }

  if (ret)
    cout << "O" << endl;
  else
    cout << "X" << endl;
  
  return 0;
}