Problem Description

Paken-kun hosted a programming contest over two days. On the first day, $N$ people participated, and on the second day, $M$ people participated.

Each participant was assigned an integer ID. The IDs of the participants on the first day were $A_1, A_2, \ldots, A_N$, and the IDs of the participants on the second day were $B_1, B_2, \ldots, B_M$. No two different people were assigned the same ID.

Paken-kun wants a list of IDs of people who satisfy the following condition:

• Did not participate in the contest on the first day but participated on the second day.

Please list the IDs of people who satisfy this condition on behalf of Paken-kun.

Input Format

The input is given from the standard input in the following format:

$N$ $M$ $A_1$ $A_2$ $\ldots$ $A_N$ $B_1$ $B_2$ $\ldots$ $B_M$

Output Format

Let $K$ be the number of people who satisfy the condition.

First, output $K$ in the first line. Then, for each of the $K$ people, output their ID on a new line.

The IDs can be output in any order.

Sample Input and Output

Sample Input #1

3 4
1 3 4
6 8 3 1

Sample Output #1

2
6
8

Sample Input #2

4 3
8 4 2 1
1 4 2

Sample Output #2

0

Sample Input #3

3 2
1234 312 999
888 519

Sample Output #3

2
519
888

Sample Input #4

10 8
14 9 3 8 11 18 20 12 16 17
6 4 5 18 11 14 19 20

Sample Output #4

4
4
5
6
19

Notes/Hints

Constraints

• $1 \leq N \leq 3000$
• $1 \leq M \leq 3000$
• $1 \leq A_i \leq 3000$
• $1 \leq B_i \leq 3000$
• $i \neq j \implies A_i \neq A_j$
• $i \neq j \implies B_i \neq B_j$
• All input values are integers.

Sample Explanation 1

The person with ID $6$ and the person with ID $8$ did not participate in the contest on the first day but participated on the second day. The IDs can be output in any order, so the following output is also correct: 2 8 6

Sample Explanation 2

There may be no people who satisfy the condition.

Sample Explanation 4

Original idea: Forested

见题面 Input 部分

见题面 Output 部分