#include <stdio.h>

 #include <string.h>

 const int maxn = ;

 const int maxm = *;

 int head[maxn],vis[maxm];

 struct node

 {

     int u;

     int v;

     int next;

 } edge[maxm];

 int n,m,cnt;

 void init()

 {

     memset(head,-,sizeof(head));

     memset(vis,,sizeof(vis));

     cnt = ;

 }

 void add(int u,int v)

 {

     edge[cnt].u = u;

     edge[cnt].v = v;

     edge[cnt].next = head[u];

     head[u] = cnt++;

 }

 void dfs(int u)

 {

     for (int i = head[u]; i!=-; i = edge[i].next)

     {

         if (!vis[i])

         {

             vis[i] = ;

             dfs(edge[i].v);

         }

     }

     printf("%d\n",u);

 }

 int main()

 {

     scanf("%d%d",&n,&m);

     init();

     for (int i = ; i < m; i ++)

     {

         int u,v;

         scanf("%d%d",&u,&v);

         add(u,v);

         add(v,u);

     }

     dfs();

     return ;

 }