N, S = [input() for _ in range(2)]

def main(n, s):
	found_list = []
	for i in range(int(n) - 2):
		if '404' == s[i:i+3]:
			found_list.append(s[i:i+3])
	if len(found_list) == 0:
		print('NotFound')
	else:
		print('Found')

if __name__ == '__main__':
	main(N, S)