Example

Input

5 3
4
2
5


Output

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

typedef int _loop_int;
#define REP(i,n) for(_loop_int i=0;i<(_loop_int)(n);++i)
#define FOR(i,a,b) for(_loop_int i=(_loop_int)(a);i<(_loop_int)(b);++i)
#define FORR(i,a,b) for(_loop_int i=(_loop_int)(b)-1;i>=(_loop_int)(a);--i)

#define DEBUG(x) cout<<#x<<" : "<<x<<endl
#define ALL(v) (v).begin(),(v).end()

int n,m;
int q[125252];
int po[252521];
int tail;
bool used[252521];

int main(){
  scanf("%d%d",&n,&m);
  REP(i,m)scanf("%d",q+i);
  tail=0;
  FORR(i,0,m){
    int a = q[i]-1;
    if(!used[a]){
      po[tail++] = a;
      used[a] = true;
    }
  }
  REP(i,n)if(!used[i])po[tail++] = i;
  REP(i,n){
    printf("%d\n",po[i]+1);
  }
  return 0;
}