def main():
	n_str = input()
	n = int(n_str)

	assert 1 <= n <= 200
	assert str(n) == n_str

	for i in range(n):
		line = input()
		a, b = tuple(map(int, line.split()))

		assert 1 <= max(a, b) <= 10**5
		assert 1 <= min(a, b) <= 10**3
		assert ' '.join(map(str, (a, b))) == line

	print('OK')


if __name__ == '__main__':
	main()