#include <bits/stdc++.h>

using namespace std;

const long long N = 2e5 + 7;

long long int_rand(){
	long long c = (1 << 15);

	return (rand() % c) * c + (rand() % c);
}

vector<long long> adj[N];

clock_t t;

bool time_left(){
	if((float) (clock() - t) / CLOCKS_PER_SEC <= 4.6)
		return true;

	return false;
}

bool used[N];
long long parent[N], cnt[N];

long long n;

vector<long long> dfs_vector;
long long d[N];

void dfs(long long from){
	stack<long long> st;
	queue<long long> q;

	st.push(from);
	used[from] = true;
	d[from] = 1;

	long long from2 = from, best = from;

	//cout << "\n";

	while(!st.empty()){
		from = st.top();
		st.pop();

		if(d[from] > d[best])
			best = from;

		for(long long i = cnt[from]; i < adj[from].size(); i++){
			long long x = adj[from][i];

			if(!used[x]){
				used[x] = true;
				parent[x] = from;
				d[x] = d[from] + 1;
				st.push(from);
				cnt[from]++;
				st.push(x);

				break;
			}
		}
	}

	from = best;

	while(from != from2)
	{
		dfs_vector.push_back(from);
		from = parent[from];
	}

	dfs_vector.push_back(from);

	//cin.get();

	//cout << from << " " << dfs_vector.size() << "\n";
}

void solve(long long x){
	//cout << x << "\n";

	for(long long i = 1; i <= n; i++){
		used[i] = false;
		cnt[i] = 0;
	}

	dfs_vector.clear();

	dfs(x);

	for(long long i = 1; i <= n; i++){
		used[i] = false;
		cnt[i] = 0;
	}

	for(long long i: dfs_vector){
		used[i] = true;
	}

	dfs_vector.pop_back();
	vector<long long> curr = dfs_vector;

	dfs_vector.clear();

	dfs(x);

	reverse(dfs_vector.begin(), dfs_vector.end());

	for(int y: dfs_vector){
		curr.push_back(y);
	}

	dfs_vector = curr;
}

long long calc_score(vector<long long> v){
	long long score = 0;

	for(int i = 0; i < v.size(); i++)
		score += v[i] * (i + 1);

	return score;
}

vector<long long> res, curr;
long long res_score, curr_score;

vector<long long> try_reverse(vector<long long> v){
	std::vector<long long> rev;

	rev = v;
	reverse(rev.begin(), rev.end());

	if(calc_score(rev) > calc_score(v))
		return rev;

	return v;
}

long double C;

bool cmp(long long lvalue, long long rvalue){
	return (long double)lvalue - C*(long double)adj[lvalue].size() > (long double)rvalue - C*(long long)adj[rvalue].size();
}

int main (){
	ios::sync_with_stdio(false);
	cin.tie(NULL);

	t = clock();

	freopen("maxpath.in", "r", stdin);
	freopen("maxpath.out", "w", stdout);

	long long m;

	cin >> n >> m;

	if(n <= 100)
		C = -2;
	else
		if(n == 1000)
			C = 5;
		else
			C = 15000;

	for(long long i = 0; i < m; i++){
		long long u, v;

		cin >> u >> v;

		adj[u].push_back(v);
		adj[v].push_back(u);
	}

	for(int i = 1; i <= n; i++){
		sort(adj[i].begin(), adj[i].end(), cmp);
	}

	solve(n);

	//res = try_reverse(dfs_vector);
	res_score = calc_score(res);

	do{
		long long x = n + 1;

		while(time_left() && x > 1){
			x--;

			solve(x);

			//dfs_vector = try_reverse(dfs_vector);
			curr_score = calc_score(dfs_vector);

			if(curr_score > res_score){
				res_score = curr_score;
				res = dfs_vector;
			}

			if(n == 100000){
				C -= 100;	
			}
		}

		if(n <= 100){
			C += 0.1;
		}
		else{
			C = rand() % n + 1;
		}

		if(!time_left()){
			break;
		}

		for(int i = 1; i <= n; i++){
			sort(adj[i].begin(), adj[i].end(), cmp);
		}
	}
	while(true);

	//cout << res_score << endl;

	cout << res.size() << "\n";

	for(int x: res){
		cout << x << "\n";
	}

	return 0;
}
/*
6 10
3 4
3 2
3 5
4 6
4 2
2 5
2 1
1 6
2 6
5 1
*/