#include<cstdio>

 #include<iostream>

 #include<cstring>

 #include<algorithm>

 using namespace std;

 const int maxn=,maxm=;

 struct zs{

     int too,pre;

 }e[maxm<<],e1[maxm<<];int tot,last[maxn],tot1,last1[maxn];

 int u[maxm],v[maxm];

 int fa[maxn];

 int i,j,k,n,m;

 inline void insert(int a,int b){

     if(e[last[a]].too==b)return;

     e[++tot].too=b,e[tot].pre=last[a],last[a]=tot;

 }

 inline void ins(int a,int b){

     e1[++tot1].too=b,e1[tot1].pre=last1[a],last1[a]=tot1;

 }

 int getfa(int x){

     return fa[x]!=x?fa[x]=getfa(fa[x]):x;

 }

 void dfs(int x){

     fa[x]=x+;

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

     int next=getfa();//printf("  next:%d\n",next);

     for(int i=last[x];i;i=e[i].pre){

         while(next<e[i].too)

             dfs(next),next=getfa(next+);

         if(next==e[i].too)next=getfa(next+);

     }

     while(next<=n)dfs(next),next=getfa(next+);

 }

 int ra;char rx;

 inline int read(){

     rx=getchar(),ra=;

     while(rx<''||rx>'')rx=getchar();

     while(rx>=''&&rx<='')ra*=,ra+=rx-,rx=getchar();return ra;

 }

 int main(){

     n=read(),m=read();

     for(i=;i<=m;i++)u[i]=read(),v[i]=read(),ins(v[i],i),ins(u[i],i);

     for(i=n;i;fa[i]=i,i--)

         for(j=last1[i];j;j=e1[j].pre)

             if(j&)insert(u[e1[j].too],i);

             else insert(v[e1[j].too],i);

 //  for(i=1;i<=n;i++)for(j=last[i];j;j=e[j].pre)printf("%d-->%d\n",i,e[j].too);//return 233;

     fa[n+]=n+;

     dfs();

     return ;

 }