## rectperimeter
### Instructions
Write a function that takes two `int` 's as arguments, representing the length of width and height of a rectangle and returning the perimeter of the rectangle.
- If one of the arguments is negative it should return `-1` .
### Expected function
```go
func RectPerimeter(w, h int) int {
}
```
### Usage
Here is a possible program to test your function:
```go
package main
import (
"fmt"
"piscine"
)
func main() {
fmt.Println(piscine.RectPerimeter(10, 2))
fmt.Println(piscine.RectPerimeter(434343, 898989))
fmt.Println(piscine.RectPerimeter(10, -2))
}
```
And its output:
```console
$ go run .
24$
2666664$
-1$
$
```
