import sys, math
input = lambda: sys.stdin.readline()[:-1]
def MI(): return map(int, input().split())
inf = 10**18

n, = MI()
print("X" if n%4==3 else "O")

# res = 0
# for i in range(1, n+1):
#     res ^= i
#     if res==0:
#         print(i)