#include <algorithm>
#include <bitset>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <tuple>
#include <vector>

using namespace std;

#define rep(i, n) for (int64_t i = 0; i < (int64_t)(n); i++)
#define irep(i, n) for (int64_t i = 0; i <= (int64_t)(n); i++)
#define rrep(i, n) for (int64_t i = (n)-1; i >= 0; i--)
#define rirep(i, n) for (int64_t i = n; i >= 0; i--)

#define chmax(a, b) (a) = max(a, b)
#define chmin(a, b) (a) = min(a, b)

int64_t fill_ones(int64_t a) {
  a |= a >> 1;
  a |= a >> 2;
  a |= a >> 4;
  a |= a >> 8;
  a |= a >> 16;
  a |= a >> 32;
  return a;
}

int64_t msb(int64_t a) { return (fill_ones(a) + 1) >> 1; }

unsigned int calc(unsigned int N) {
  if (N == 0) {
    return 0;
  }
  unsigned int m = msb(N);
  return (m / 2 <= 1 ? (m - 1) : 0) ^ calc(N - m) ^
         ((N - m + 1) % 2 == 1 ? m : 0);
}

int main() {
  unsigned int N;
  cin >> N;

  cout << (calc(N) == 0 ? "X" : "O") << endl;

  return 0;
}