#include <bits/stdc++.h>
using namespace std;

ifstream ci("dfs.in");
ofstream cou("dfs.out");

int n,m;
vector<int>v[100005];
int viz[100005];

void citire(){
    ci>>n>>m;
    for(int i=1;i<=m;i++){
        int x,y;
        ci>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void Dfs(int x){
    viz[x]=1;
    cout<<x<<"\n";
    for(auto i:v[x]){
        if(viz[i]==0){
            Dfs(i);
        }
    }
}

void rez(){
    int cn=0;
    for(int i=1;i<=n;i++){
        if(viz[i]==0){
            cn++;
            Dfs(i);
        }
    }
    cou<<cn;
}

int main()
{
    citire();
    rez();
    return 0;
}