#include <fstream>
using namespace std;
ifstream fin("sortaret.in");
ofstream fout("sortaret.out");
struct nod
{
    int info;
    nod *next;
};
nod *p,*l[50001];
int x,y,i,j,n,nods,viz[50001],st[100001],niv,z,ga,m;
int main()
{
    fin>>n>>m;
    for(i=1;i<=m;++i)
    {
        fin>>x>>y;
        p=new nod;
        p->info=y;
        p->next=l[x];
        l[x]=p;
        if(nods==0)
            nods=x;
    }
    niv=1;
    viz[nods]=1;
    st[niv]=nods;
    fout<<nods<<" ";
    while(niv)
    {
        z=st[niv];
        ga=0;
        while(l[z]&&ga==0)
        {
            if(viz[l[z]->info]==0)
            {
                st[++niv]=l[z]->info;
                ga++;
                viz[l[z]->info]=1;
                fout<<l[z]->info<<" ";
            }
            l[z]=l[z]->next;
        }
        if(ga==0)
            niv--;
    }

    return 0;
}