n=int(input())
list1=[]
for i in range(1,n//4+1):
    if (n-i*4)%7==0:
        list1.append("4"*i+"7"*((n-4*i)//7))

for j in range(1,n//7+1):
    if (n-j*7)%4==0:
        list1.append("4"*((n-j*7)//4)+"7"*j)


if len(list1) == 0:
    print(-1)
else:
    list2=[]
    for k in range(0,len(list1)):
        list2.append(int(list1[k]))
    list2.sort()
    print(list2[0])