#include<algorithm>
#include<iostream>
#include<fstream>
#include<cstring>
#include<vector>
#include<ctime>
using namespace std;
int cmp (int x, int y)
{
    return x>y;
}
int n,m;
bool used[100005];
int z[100005],ans[100005],ansSize;
long long c;
vector<int> v[100005];
double t;

void dfs (int pos, int num, long long score)
{
    if ((clock()-t)/CLOCKS_PER_SEC>=4.8)
        return;

    used[pos]=true;
    score+=(long long)num*pos;
    z[num-1]=pos;

    bool flag=true;

    for (int i=0; i<v[pos].size(); i++)
        if (!used[v[pos][i]])
        {
            dfs(v[pos][i],num+1,score);
            flag=false;
        }

    if (flag && score>c)
    {
        for (int i=0; i<num; i++)
            ans[i]=z[i];
        c=score;
        ansSize=num;
    }
    if (flag)
    {
        long long newscore=0;
        int br=1;
        for (int i=num-1; i>=0; i--)
        {
            newscore+=(long long)z[i]*br;
            br++;
        }
        if (newscore>c)
        {
            for (int i=num-1; i>=0; i--)
                ans[num-i-1]=z[i];
            c=newscore;
            ansSize=num;
        }
    }
    used[pos]=false;
}

int main()
{
    t=clock();
    freopen ("maxpath.in", "r", stdin);
    freopen ("maxpath.out", "w", stdout);

	ios::sync_with_stdio (false);
	cin.tie (nullptr);
	cout.tie (nullptr);

    cin>>n>>m;
    for (int i=0; i<m; i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (int i=1; i<=n; i++)
        sort(v[i].begin(),v[i].end(),cmp);

    for (int i=n; i>=1; i--)
    {
        if ((clock()-t)/CLOCKS_PER_SEC>=4.8)
            break;
        //memset(used,0,sizeof(used));
        dfs(i,1,0);
    }

    cout<<ansSize<<'\n';
    for (int i=0; i<ansSize; i++)
        cout<<ans[i]<<'\n';

    return 0;
//    fin.close();
//    fout.close();
}