Spring Outing

Problem Description

A teacher takes the students on a spring outing. There are $N$ students in the class, each with a unique ID from $0$ to $N-1$. At assembly time, the teacher wants to confirm whether all students have arrived, so the students call out their IDs. Every student who arrives will call out their own ID (never someone else's), but some naughty students may call out multiple times. Can you help the teacher find out which students have not arrived?

Input Format

The input contains $2$ lines. The first line contains two integers $N$ and $M$, meaning the class has $N$ students and the students call out their IDs $M$ times in total. The second line contains $M$ integers, the IDs called out in the $M$ times. All IDs are non-negative integers less than $N$.

Output Format

Output one line. If all students have arrived, output $N$; otherwise output all IDs of students who have not arrived, in ascending order, separated by spaces.

Sample Input 1

3 3
0 2 1

Sample Output 1

3

Sample Input 2

3 5
0 0 0 0 0

Sample Output 2

1 2

Sample Explanation

For the first sample, the class has $N=3$ students with IDs $0$, $1$, $2$. The $M=3$ called-out IDs are $0$, $2$, $1$ in order, which exactly covers all student IDs, meaning every student arrived. So we output the value of $N$, which is $3$.

Constraints

• $2 \le N, M \le 1000$
• All called-out IDs satisfy $0 \le \text{ID} \le N-1$