import sys
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
mod = 10**9 + 7
inf = float('inf')

N =I()
T = []

#print(T)
judge = int(0)
for i in range(N):
    judge ^= (i+1)

if judge==0:
    ans = "X"
else:
    ans = "O"
print(ans)