#include<iostream>
#include<cstring> 
#include<algorithm>
#include<vector>
using namespace std;

const int N=5e5+10;
int n, m, ans[N], cnt, p, f; 
struct node{int x, y;}tmp[N<<1];
bool cmp(node n1, node n2) 
{
	if (n1.x==n2.x) return n1.y>n2.y;
	return n1.x<n2.x;
}
struct edge{int x, y, pre;}a[N<<1];int alen, last[N<<1];
void ins(int x, int y) {alen++;a[alen]={x, y, last[x]};last[x]=alen;}

vector<int> jhs;
bool v[N], to[N], huan[N];
int stack[N], top;

void dfs(int x, int fa)
{
	ans[++cnt]=x;
	for (int k=last[x];k;k=a[k].pre)
	{
		int y=a[k].y;
		if (y==fa) continue;
		dfs(y, x);
	}
}

bool get_huan(int x, int fa)
{
	for (int k=last[x];k;k=a[k].pre)
	{
		int y=a[k].y;
		if (y==fa) continue;
		if (v[y]) 
		{
			int temp;
			do
			{
				temp=stack[top--];v[temp]=0;
				huan[temp]=1;jhs.push_back(temp);
			}while (temp!=y);
			p=temp;to[temp]=1;
			if (temp==1) return true;
			do
			{
				temp=stack[top--];v[temp]=0;
				to[temp]=1;
			}while (temp!=1);
			return true;
		}
		stack[++top]=y, v[y]=1;
		if (get_huan(y, x)) return true;
		stack[top--]=0, v[y]=0;
	}
	return false;
}

void init(int x, int fa)
{
	if (x==p) {f=fa;return ;}
	ans[++cnt]=x;v[x]=1;
	for (int k=last[x];k;k=a[k].pre)
	{
		int y=a[k].y;
		if (y==fa||v[y]) continue;
		init(y, x);
	}
}

void get_ans(int x, int fa, int lim, bool op)
{
	if (x>lim&&huan[x]&&!op) {p=x;return ;}
	else if (x==lim&&huan[x]&&op) 
	{
		ans[++cnt]=x;
		for (int k=last[x];k;k=a[k].pre)
		{
			int y=a[k].y;
			if (y==fa||huan[y]) continue;
			get_ans(y, x, lim, op);
		}
		return ;
	}
	ans[++cnt]=x;
	for (int k=last[x];k;k=a[k].pre)
	{
		int y=a[k].y;
		if (y==fa) continue;
		get_ans(y, x, lim, op);
	}
}

int main()
{
	freopen("text.out", "w", stdout);
	scanf("%d%d", &n, &m);
	for (int i=1;i<=m;i++)
	{
		int x, y;scanf("%d%d", &x, &y);
		tmp[i]={x, y};tmp[i+m]={y, x};
	}
	sort(tmp+1, tmp+2*m+1, cmp);
	for (int i=1;i<=2*m;i++) ins(tmp[i].x, tmp[i].y);
	if (m==n-1) dfs(1, 0);
	else 
	{
		v[1]=1;stack[++top]=1;get_huan(1, 0);
		for (int k=last[1];k;k=a[k].pre)
		{
			int y=a[k].y;
			if (to[y]||huan[y]) continue;
			dfs(y, 1);
		}
		memset(stack, 0, sizeof stack);
		memset(v, 0, sizeof v);top=0;
		if (1!=p) init(1, 0);
		int flag1=0, flag2=0;ans[++cnt]=p;
		for (int k=last[p];k;k=a[k].pre)
		{
			int y=a[k].y;
			if (huan[y]) 
				if (flag1) flag2=y;
				else flag1=y;
		}
		int t=p;
		for (int k=last[t];k;k=a[k].pre)
		{
			int y=a[k].y;
			if (y==f) continue;
			if (y==flag1) 
				get_ans(y, t, flag2, 0);
			else if (y==flag2)
				get_ans(y, t, p, 1);
			else dfs(y, t);
		}
	}
	for (int i=1;i<=cnt;i++) printf("%d ", ans[i]);
	return 0;
}
                           ```