Make String 1

Seohyun is the teaching assistant in charge of the physics lab this semester, and she is entering the students' grades.

The section she manages has $N$ students. Exactly half of them receive S and the other half receive U. $N$ is always even.

The grades of student 1, student 2, $\cdots$, student $N$ are given as a string $T$ of length $N$. Seohyun's job is to enter this string into the grading system.

Seohyun enters the grades by repeating only the following operations.

1. Insert SU at the cursor position.
2. If the cursor is not at the leftmost position, move the cursor one character to the left.
3. Insert US at the cursor position.

The initial state is an empty string. The cursor is always at the front, at the end, or between two characters. After operations 1 and 3, the cursor moves to just after the inserted string.

For Seohyun, find a way to enter all the grades using at most $2N$ operations.

The first line contains the length $N$ of the string ($2\le N\le 1\,000\,000$, $N$ is even).

The second line contains the string $T$ consisting only of S and U, which represents the grades. $T$ has the same number of S and U characters.

On the first line, print the number of operations $K$ ($0\le K\le 2N$).

On the second line, print a string of length $K$ describing Seohyun's operations. Operation 1 is written as S, operation 2 as N, and operation 3 as U. When the cursor is at the leftmost position, operation 2 must not be printed.

After all operations, the cursor may be anywhere.

If there are multiple answers, print any one of them.

Under the input constraints, an answer always exists, and this can be proven.