while True:
	sum=int(raw_input())
	num=""
	for i in range(sum//7+1):
		for j in range(sum//4+1):
			if 4*j+7*i==sum:
				if len(num)>(i+j) or num=="":				
					num= "4"*j+"7"*i				
	if num=="":
		print "-1"
	else:
		print num