#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

const int maxn=100005;

int n,m,cntConexe;
vector <int> g[maxn];
bool vizitat[maxn];
vector <int> comp[maxn];

void dfs(int node)
{
    vizitat[node]=1;
    cout<<node<<" ";
    for (int i=0;i<int(g[node].size());i++)
    {
        int vecin=g[node][i];
        if (!vizitat[vecin])
            dfs(vecin);
    }
}
int main ()
{
    fin>>n>>m;
    for (int i=1;i<=m;i++)
    {
        int x,y;
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for (int i=1;i<=n;i++)
    {
        if (!vizitat[i])
        {
            cntConexe++;
            dfs(i);
        }
    }
    fout<<cntConexe;
    return 0;
}