#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;

    ll ans = 0;
    for (ll i = 1; i <= N; i++) {
        ans ^= i;
    }
    // cout << ans << endl;
    if (ans != 0) {
        cout << "O" << endl;
    } else {
        cout << "X" << endl;
    }
}