n = int(input())
s = n
num7 = -1

for i in range(0,n//4+1):
    if s % 7 == 0:
        num7 = s // 7
        print('4'*i + '7'*num7)
        break
    s = s - 4
else:
    if n%4 != 0:
        print("-1")
    else:
        print('4'*i)