#include <bits/stdc++.h>
// #include <atcoder/all>
// using namespace atcoder;
#include <string>
#include <vector>
#include <algorithm>
#define rep(i,n) for (int i = 0;i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define chmax(x,y) x = max(x,y)
using R=double;
using ld = long double;
int INF = 1e9;
using graph = vector<vector<int>>;

//using mint = modint1000000007;

int main(){
	ll n;cin >> n;
	if(n%4 == 3) cout << "X" << endl;
	else cout << "O" << endl;
}