import sys


def main():
	lines = sys.stdin.readlines()

	n_str = lines[0].rstrip('\n')
	n, m = tuple(map(int, n_str.split()))

	assert 1 <= n <= 100000
	assert 0 <= m <= 100000
	assert ' '.join(map(str, (n, m))) == n_str
	assert len(lines) == m + 2

	# for i in range(n):
	# 	line = lines[i + 1].rstrip('\n')
	# 	a, b = tuple(map(int, line.split()))

	# 	assert 1 <= a <= N
	# 	assert 1 <= b <= N
	# 	assert ' '.join(map(str, (a, b))) == line

	print('OK')


if __name__ == '__main__':
	main()