Start: Jul, 17, 2019 00:00:00
20190717Python程序设计基础培训第三次作业
End: Jul, 21, 2019 00:00:00
Time elapsed:
Time remaining:

Problem_ID: E
Result: Accepted
Time: 46ms
Memory: 25316kB
Author: 13666594886
In contest: 1295

n=int(input())
i=n//7
while i>=0:
    if (n-i*7)%4==0:
        print("4"*((n-i*7)//4)+"7"*i)
        break
    i=i-1
else:
    print(-1)