D. Explosive String
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

There's a $$$1 \times n$$$ grid. For a string $$$y$$$ of length $$$l$$$, a robot moves according to the following pattern.

  • Initially, the robot selects a cell as the starting point.
  • Then, in the $$$i$$$-th $$$(1 \leq i \leq l)$$$ move, if $$$y_i = \mathtt{L}$$$, the robot moves one cell to the left; if $$$y_i = \mathtt{R}$$$, it moves one cell to the right. If the robot moves out of bounds, it explodes.

You are given a possibly incomplete string $$$x$$$ of length $$$m$$$. Your task is to complete the string $$$x$$$ such that, regardless of which cell the robot selects as the starting point, it will always explode. If there's no such string, output "NO" instead.

Input

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 1000$$$). The description of the test cases follows.

The first line of each test case contains two integers $$$n$$$ and $$$m$$$ ($$$1 \le n,m \le 50$$$).

The second line of each test case contains a string $$$x_1x_2 \ldots x_{m}$$$ of length $$$m$$$ consisting of characters 'L', 'R' and '?'. If $$$x_i=\mathtt{?}$$$ ($$$1 \le i \le m$$$), it means you need to choose 'L' or 'R' as the value of $$$x_i$$$.

Output

For each test case, if there's no such string, output "NO" in a new line. Otherwise, output "YES" in a new line, then output the complete string $$$x$$$ in the next line.

Example
Input
4
1 1
L
2 1
?
3 5
LR?R?
50 5
?????
Output
YES
L
NO
YES
LRRRL
NO
Note

In the first test case, the robot can only choose the first cell as the start point. Then, in the first move, the robot moves one cell to the left, which is out of bounds. After the first move, the robot will explode, so the answer is "YES".

In the second test case, if $$$x=\mathtt{L}$$$, the robot can choose the second cell as the start point. If $$$x=\mathtt{R}$$$, the robot can choose the first cell as the start point. In both cases, the robot will not explode. Thus, the answer is "NO".