#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;


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

  if(N%4==3) cout << "X" << endl;
  else cout << "O" << endl;
  
  /*
  REP(N,1,100){
    int x = 0;
    for(int i=1; i<=N; i++) x ^= i;

    cout << N << " ";
    if(x!=0) cout << "O" << endl;
    else cout << "X" << endl;

  }
  */
  return 0;
}