from itertools import groupby

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, 'oo-')
    ok |= check(s, '-oo')
    ok |= check(s, '-o--')
    ok |= check(s, '--o-')
    gb = groupby(list(s))
    gbl = [(k, len(list(v))) for k, v in gb]
    for i in range(len(gbl) - 2):
        a,b,c = gbl[i : i + 3]
        if a[0] == 'o' and b[0] == '-' and c[0] == 'o' and b[1] % 2 == 1:
            ok = True
            break
    print("XO"[ok])