CF109A Lucky Sum of Digits

Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not. Petya wonders eagerly what minimum lucky number has the sum of digits equal to $ n $ . Help him cope with the task.

The single line contains an integer $ n $ ( $ 1

Print on the single line the result — the minimum lucky number, whose sum of digits equals $ n $ . If such number does not exist, print -1.