Eric has a lot of shoes, way too many shoes.

On the floor, there are shoes, labelled from to . Each of them are either for his left foot or for his right foot, and he wants to pair up **each** left shoe with a right shoe.

As there is more than one possible answer, you may output any of them. Furthermore, the input is guaranteed to have at least one valid solution.

#### Constraints

, representing if the shoe is left or right, will always be equal to `L`

or `R`

. The amount of `L`

and `R`

will always be the same.

#### Input Specification

The first and only line of input will contain space-separated characters, , where represents the index of the shoe.

#### Output Specification

You are to output pairs of integers , each on a separate line. Each pair represents a pair of shoes made between shoe and shoe .

The pairs can be printed in any order, and the numbers within each pair can be printed in any order.

#### Sample Input

`L R L R`

#### Sample Output

```
1 2
3 4
```

#### Sample Explanation

We can pair up the first 2 shoes, and the last 2 shoes in order to make pairs. Another valid solution is to pair up the first and last shoe, and then the 2nd and 3rd shoe.

## Comments