for _ in range(int(input())):
	_, s = input().split()
	ok = 0
	if 'ooo' in s or '-oo' in s or 'oo-' in s or '-o--' in s or '--o-' in s:
		ok = 1
	for i in range(1, 999, 2):
		if 'o' + '-' * i + 'o' in s:
			ok = 1
	print("XO"[ok])