N = int(input())
sAll = [input() for i in range(N)]

search = ["ooo", "oo-", "-oo", "-o--", "--o-"]
for i in range(1, 499):
    search.append("o" + ("-"*(2*i-1)) + "o")
    
for sLine in sAll:
    n, s = sLine.split()
    flag = False
    for win in search:
        if win in s:
            flag = True
            break
    print("O" if flag else "X")