#include<iostream>
using namespace std;

int main()
{
	int M, N, ans = 0, a[1005];
	cin >> N >> M;
	for (int i = 0; i < M; i++)
	{
	    int y;
	    cin >> y;
	    a[y] = 1;	 
	}
	
	for (int i = 0; i < N; i++)
	{
	    if (a[i] == 1)
		{
	        ans++;	
	        cout << i << " "; 
	    }
	}
	
	if (ans == 0)
	{
		cout << N;
	}
   
	return 0;
}