T = int(input())

def check(s, pattern):
    return s.count(pattern) > 0

for _ in range(T):
    _, s = input().split()
    ok = False
    ok |= check(s, 'ooo')
    ok |= check(s, 'o-o')
    ok |= check(s, 'oo-')
    ok |= check(s, '-oo')
    ok |= check(s, '-o--')
    ok |= check(s, '--o-')
    print("XO"[ok])