#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define sz(x) int(x.size())
using namespace std;

typedef long long ll;
const int INF = 1e8;
// const ll INF = 1LL << 60;
typedef pair<int, int> P;

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

    // 桁ごとに xor を計算する
    // for (ll i = 1; i <= N; i++) {
    //     ans ^= i;
    // }

    N++;
    ll ans = 0;
    for (int i = 0; i < 50; i++) {
        ll loop = (1LL << (i + 1));
        ll cnt = (N / loop) * (loop / 2);
 
        cnt += max(0LL, (N % loop) - (loop / 2));
        if (cnt % 2 == 1) {
            ans += 1LL << i;
        }
    }

    // cout << ans << endl;
    if (ans != 0) {
        cout << "O" << endl;
    } else {
        cout << "X" << endl;
    }
}