#include <fstream>
using namespace std;
ifstream in("numere25.in");
ofstream out("numere25.out");

int main()
{
    int x,nr,last = 1;

    bool ok = false;

    in>>x;

    in>>nr;

    for(int i=1;i<nr;i++){
        out<<i<<" ";
        ok = true;
    }

    last = nr;

    while(in>>nr)
    {
        for(int i = last+1;i<nr;i++){
            out<<i<<" ";
            ok = true;
        }
        last = nr;
    }

    for(int i = last +1;i<=x;i++){
        out<<i<<" ";
        ok = true;
    }

    if(!ok)
        out<<"Nu exista"<<'\n';
}