#include <cstdio>
#include <algorithm>
using namespace std;
const int N=500005;
const int M=1000005;
int n,m;
int u,v;
int h[N],nx[M],to[M],cnt;
int dfn[N],low[N],idx;
int s[N],t;
bool vis[N];
int loop[N],lcnt;
bool inloop[N],pass[N];
int f[N],scnt,fir,lim,cut;
int mv[N];
bool forbid[M];
int matu[M],matv[M],matp[M],matc;
int aeh[N],aenx[M],aeto[M],aecnt;
bool cmp(int u,int v)
{
return matv[u]>matv[v];
}
void aeforl(int u,int v)
{
aecnt++;
aeto[aecnt]=v;
aenx[aecnt]=aeh[u];
aeh[u]=aecnt;
}
void addedge(int u,int v)
{
cnt++;
to[cnt]=v;
nx[cnt]=h[u];
h[u]=cnt;
}
void greedy(int u,int p)
{
printf("%d ",u);
for (int i=h[u];i;i=nx[i])
if (to[i]!=p)
greedy(to[i],u);
}
void findloop(int u,int las)
{
idx++;
dfn[u]=low[u]=idx;
t++;
s[t]=u;
vis[u]=1;
for (int i=aeh[u];i;i=aenx[i])
if (i!=(las^1))
if (!vis[aeto[i]])
{
findloop(aeto[i],i);
if (low[aeto[i]]<low[u])
low[u]=low[aeto[i]];
}
else
if (dfn[aeto[i]]<low[u])
low[u]=dfn[aeto[i]];
if (dfn[u]==low[u])
{
if (s[t]==u)
t--;
else
{
while (s[t]!=u)
{
lcnt++;
loop[lcnt]=s[t];
t--;
}
lcnt++;
loop[lcnt]=u;
t--;
}
}
}
void flag(int u,int p)
{
if (u==1)
pass[u]=1;
for (int i=h[u];i;i=nx[i])
if (to[i]!=p&&inloop[to[i]]==0)
{
flag(to[i],u);
pass[u]|=pass[to[i]];
}
}
void dfs(int u,int p)
{
printf("%d ",u);
for (int i=h[u];i;i=nx[i])
if (to[i]!=p&&forbid[i]==0)
dfs(to[i],u);
}
int main()
{
scanf("%d%d",&n,&m);
aecnt++;
for (int i=1;i<=m;i++)
{
scanf("%d%d",&u,&v);
aeforl(u,v);
aeforl(v,u);
matc++;
matu[matc]=u;
matv[matc]=v;
matp[matc]=matc;
matc++;
matu[matc]=v;
matv[matc]=u;
matp[matc]=matc;
}
sort(matp+1,matp+matc+1,cmp);
for (int i=1;i<=matc;i++)
addedge(matu[matp[i]],matv[matp[i]]);
if (n>m)
{
greedy(1,0);
printf("\n");
}
else
{
findloop(1,0);
for (int i=1;i<=lcnt;i++)
inloop[loop[i]]=1;
flag(loop[lcnt],0);
for (int i=1;i<=lcnt;i++)
for (int j=h[loop[i]];j;j=nx[j])
if (pass[to[j]]==0&&inloop[to[j]]==0)
if (to[j]>mv[loop[i]])
mv[loop[i]]=to[j];
scnt=0;
for (int i=h[loop[lcnt]];i;i=nx[i])
if (!pass[to[i]])
{
scnt++;
f[scnt]=to[i];
}
sort(f+1,f+scnt+1);
for (fir=1;fir<=scnt;fir++)
if (inloop[f[fir]])
break;
lim=f[fir+1];
if (f[fir]==loop[1])
{
for (cut=1;cut<lcnt;cut++)
{
if (mv[loop[cut]]>loop[cut+1])
{
lim=n+1;
for (int i=h[loop[cut]];i;i=nx[i])
if (to[i]>loop[cut+1]&&inloop[to[i]]==0)
if (to[i]<lim)
lim=to[i];
}
if (loop[cut+1]>lim||cut+1==lcnt)
break;
}
for (int i=h[loop[cut]];i;i=nx[i])
if (to[i]==loop[cut+1])
forbid[i]=1;
for (int i=h[loop[cut+1]];i;i=nx[i])
if (to[i]==loop[cut])
forbid[i]=1;
}
else
{
loop[0]=loop[lcnt];
for (cut=lcnt-1;cut>0;cut--)
{
if (mv[loop[cut]]>loop[cut-1])
{
lim=n+1;
for (int i=h[loop[cut]];i;i=nx[i])
if (to[i]>loop[cut-1]&&inloop[to[i]]==0)
if (to[i]<lim)
lim=to[i];
}
if (loop[cut-1]>lim||cut-1==0)
break;
}
for (int i=h[loop[cut]];i;i=nx[i])
if (to[i]==loop[cut-1])
forbid[i]=1;
for (int i=h[loop[cut-1]];i;i=nx[i])
if (to[i]==loop[cut])
forbid[i]=1;
}
dfs(1,0);
printf("\n");
}
return 0;
}