#include <fstream>
#include <set>
//#include <iostream>
#include <ctime>
#include <cstdlib>

#define N 100000

using namespace std;

int n, m;
set<int> g[N];

unsigned long long bs = 0, cs;
int bestPath[N], currentPath[N], bl = 0, cl = 0;
bool used[N];
clock_t start;
const clock_t TC = 2.45 * CLOCKS_PER_SEC;

void printBestPath(bool f)
{
	ofstream out;
	out.open("maxpath.out");
	/*
	for(int i = 0; i < n; ++i)
	{
		out << i+1 << ": ";
		for(set<int>::iterator j = g[i].begin(); j != g[i].end(); ++j)
		{
			out << (*j)+1 << " ";
		}
		out << endl;
	}
	*/
	out << bl << endl;
	for(int i = bl-1; i >= 0; --i)
	{
		out << bestPath[i]+1 << endl;
	}
	out.close();
	if(f)
	{
		exit(0);
	}
}

unsigned long long evalCurrentPath()
{
	unsigned long long s = 0;
	for(int i = 0; i < cl; ++i)
	{
		s += (currentPath[i]+1) * (cl-i);
	}
	return s;
}

void DFS(int i)
{
	//cout << "DFS: " << i+1 << endl;
	if((cs = evalCurrentPath()) > bs)
	{
		bs = cs;
		for(int j = 0; j < cl; ++j)
		{
			bestPath[j] = currentPath[j];
		}
		bl = cl;
	}
	if(clock() - start >= TC)
	{
		printBestPath(1);
	}
	for(set<int>::reverse_iterator it = g[i].rbegin(); it != g[i].rend(); ++it)
	{
		int current = *it;
		if(used[current])
		{
			continue;
		}
		used[current] = 1;
		currentPath[cl++] = current;
		DFS(current);//cout << "cur: " << current+1 << endl;
		used[current] = 0;
		--cl;
	}
}

int main()
{
	start = clock();
	ifstream inp;
	inp.open("maxpath.in");
	inp >> n >> m;
	int a1, a2;
	for(int i = 0; i < m; ++i)
	{
		inp >> a1 >> a2;
		g[a1-1].insert(a2-1);
		g[a2-1].insert(a1-1);
	}
	inp.close();
	
	for(int k = n-1; k >= 0; --k)
	{	
		for(int i = 0; i < n; ++i)
		{
			used[i] = 0;
		}
		used[k] = 1;
		currentPath[0] = k;
		cl = 1;
		DFS(k);
		//cout << endl;
	}
	
	printBestPath(0);
	//cout << "Elapsed time: " << (float)(clock() - start) / CLOCKS_PER_SEC << endl;
	return 0;
}