Start: Apr, 17, 2017 10:00:00
Python程序设计基础培训第三次作业
End: Apr, 23, 2017 14:00:00
Time elapsed:
Time remaining:

Problem_ID: E
Result: Accepted
Time: 108ms
Memory: 21428kB
Author: 13175218570
In contest: 1087

n=int(raw_input())
flag=0
for i in range(n//7,-1,-1):
	if (n-7*i)%4==0:
		print '4'*((n-7*i)/4)+'7'*i
		flag=1
		break
if flag==0:print "-1"