Example

Input

5 3
4
2
5


Output

5
2
4
1
3
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

#define fi first
#define se second
#define repl(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define rep(i,n) repl(i,0,n)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define mmax(x,y) (x>y?x:y)
#define mmin(x,y) (x<y?x:y)
#define maxch(x,y) x=mmax(x,y)
#define minch(x,y) x=mmin(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt __builtin_popcount

#define INF 1e16
#define mod 1000000007

int n,m;
bool used[200010];
vector<int> a;

int main(){
  cin>>n>>m;
  rep(i,m){
    int aa;
    cin>>aa;
    aa--;
    a.push_back(aa);
  }
  reverse(all(a));
  vector<int> res;
  rep(i,m){
    if(used[a[i]])continue;
    used[a[i]]=true;
    res.push_back(a[i]);
  }
  rep(i,n)if(!used[i])res.push_back(i);
  rep(i,n)cout<<res[i]+1<<endl;
  return 0;
}

