4102: CF109 - A. Lucky Sum of Digits
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Description
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.
Input
The single line contains an integer $n\ (1≤n≤10^6)$ − the sum of digits of the required lucky number.
Output
Print on the single line the result − the minimum lucky number, whose sum of digits equals $n$. If such number does not exist, print $-1$.
Sample 1 Input
11
Sample 1 Output
47
Sample 2 Input
10
Sample 2 Output
-1