CF109A.Lucky Sum of Digits

普及/提高-

通过率：0%

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题目描述

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.

输入格式

The single line contains an integer $n$ ( $1<=n<=10^{6}$ ) — the sum of digits of the required lucky number.

输出格式

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.

输入输出样例

输入#1
```
11
```
输出#1
```
47
```
输入#2
```
10
```
输出#2
```
-1
```

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