def main():
	starts = "({["
	ends = ")}]"

	string = raw_input("String: ")
	array = []
	continueLoop = True
	for i in string:
		if not continueLoop:
			break
		if i in starts:
			array.append(i)
		if i in ends:
			counter = array.pop()
			if counter not in starts:
				print "NO!"
				continueLoop = False
			elif ends.index(i) is not starts.index(counter):
				print "NO!"
				continueLoop = False
	if continueLoop:
		if len(array) is 0:
			print "YES!"
		else:
			print "NO!"

if __name__ == "__main__":
	main()