A8199. 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 $n$ ( $1<=n<=10^{6}$ ) — the sum of digits of the required lucky number.

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.