#include<iostream>
#include<fstream>
#include<cmath>
using namespace std;
int n,m, a[100],b[100],x[100],nf, viz[100];

void citire()
{ ifstream f("date.in");
f>>n>>m; int i;
 for(i=1; i<=m;i++)
    f>>a[i]>>b[i];
}

int sol(int k)
{int nf;
if( k!=m) return 0;
else{ if(x[k]>0)nf=b[x[k]];
else nf=a[-x[k]];}
if(nf==a[x[1]])return 1;
else return 0;
}

int cond(int k)
{ int i;
 for(i=1; i<=k-1;i++)
if(abs(x[i])== abs(x[i])) return 0;
if( x[k-1]>0)nf=b[x[k-1]];
         else nf=a[x[k-1]];
if(nf==a[x[k]])return 1;
    else
      if (nf==b[x[k]])return -1;
      else return 0;
}

void afisare()
{int i,j;
cout<<a[x[1]]<<" ";
 for(i=1; i<=m ;i++)
    if(x[i]>0)cout<<b[x[i]]<<" ";
              else cout<<a[x[i]]<<" ";}

void back()
{ int i, k=2,gasit; x[1]=1;
while(k>2)
{gasit=0;
while(gasit==0 && abs(x[k])<m)
{ x[k]=abs(x[k])+1;
gasit=cond(k);
if (gasit==-1)x[k]=-x[k];
if(gasit==0)k--;
else if(sol(k)==1)afisare();
else{ k++;
      x[k]=1;}}}}

void parcurgere_df(int x)
{ int i; viz[x]=1;
 for(i=1; i<=n;i++)
if(a[x]==1 && viz[i]!=1)parcurgere_df(i);}

int conex()
{ int i; parcurgere_df(1);
for(i=1; i<=n; i++)
    if(viz[i]==0)return 0;
return 1;}

int pare()
{ int i,j;
for(i=1; i<=n; i++)
{ int d=0;
for(j=1; j<=m; j++)
    if(a[j]==i||b[j]==i)d++;
    if(d%2==1 || d==0) return 0;}
    return 1;}

int main()
{ citire();
if(conex()==1  && pare()==1)back();
else cout<<"nu este";}