#include <stdio.h>
#include <iostream>

using namespace std;
int a[1005][1005], n, m, viz[1005], cnt;

FILE *f=fopen("sortaret.in","r");
    FILE *g=fopen("sortaret.out","w");

void citire()
{

    fscanf(f,"%d %d",&n,&m);
    int i, x, y;
    for (i = 1; i <= m; i++)
    {
        fscanf(f,"%d %d",&x,&y);
        a[x][y] = a[y][x] = 1;
    }
}

void DFS(int nod)
{
    int i;
    viz[nod] = 1;   for (i = 1; i <= n; i++) if (!viz[i] && a[nod][i]) { fprintf(g,"%d\n",i); DFS(i); }
}

int main()

 {      int k=1;

       fprintf(g,"%d\n",k);
    citire();
    int i;
    for (i = 1; i <= n; i++) if (!viz[i]) { cnt++; DFS(i);}
    //printf("%d\n",cnt);

  return 0;
}