#include<bits/stdc++.h> using namespace std; int main() { int n,m,b; int a[100005]; memset(a,0,sizeof(a)); cin>>n>>m; while(m--){ cin>>b; a[b]++; } for(int i=1;i<=n;i++){ if(a[i]==0){ cout<<i<<" "; } } return 0; }