#include <bits/stdc++.h> using namespace std; bool a[1010]; int main(){ int m; int n; bool ans = true; cin >> n >> m; for (int i = 0; i<m;i++){ int x; cin >> x; a[x] = true; } for (int j = 0;j<n;j++){ if (a[j] == false){ cout << j << " "; ans = false; } } if (ans){ cout << n; } return 0; }