#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
import bisect
import heapq


def input():
    return sys.stdin.readline()[:-1]


# sys.setrecursionlimit(1000000)

# _INPUT = """3

# """
# sys.stdin = io.StringIO(_INPUT)

def f(N):
    if N == 0:
        return 0

    N1 = N
    d = 0
    while N1 > 1:
        N1 >>= 1
        d += 1
    if N % 2 == 0:
        return (1<<d) + f(N-(1<<d))
    else:
        return f(N-(1<<d))

N = int(input())
g = f(N)
if g == 0:
    print('X')
else:
    print('O')