#include<bits/stdc++.h>
using namespace std;

int main(){
	int arr[1001];
	int n,b;
	cin >>n>>b;
	int a = 0;
	for(int i = 0;i < b;i++){
		int m;
		cin >> m;
		arr[m] = 1;
	} 
	for(int i = 0;i < n;i++){
		if(arr[i]==0){
			a++;
			cout << i << " ";	
		}
	}
	if(a == 0){
		cout << n;
	}
	return 0;
}