#include<bits/stdc++.h> using namespace std; int n,m,an,ha[100001],a[100000],c[100001]; int main()na { scanf("%d%d",&m,&n); for (int i=1;i<=n;i++) { scanf("%d",&c[i]); } for (int i=n;i>=1;i--) { if (ha[c[i]]==0) { an++; a[an]=c[i]; ha[c[i]]=1; } } cout<<a[1]; for (int i=2;i<=an;i++) { cout<<" "<<a[i]; } for (int i=1;i<=m;i++) { if (ha[i]==0) { cout<<" "<<i; } } cout<<endl; return 0; }