// zsakfalvak.cpp : This file contains the 'main' function. Program execution begins and ends there.
//
#include <iostream>
#include <queue>
#include <algorithm>
#define ll long long
using namespace std;
struct adat {
bool lat = false;
vector<ll>sz;
};
vector<adat>x;
deque<ll>ans,v,zs;
ll i, n, m, akt, a, b;
void szelessegi(ll zsak)
{
while (!v.empty())
{
akt = v.front();
v.pop_front();
for (auto& e : x[akt].sz)
{
if (!x[e].lat && e != zsak)
{
if (x[e].sz.size() <= 2)
{
v.push_back(e);
ans.push_back(e);
}
else
{
ans.push_back(e);
return;
}
x[e].lat = true;
}
}
}
}
int main()
{
cin >> n >> m;
x.resize(n + 1);
for (i = 1; i <= m; ++i)
{
cin >> a >> b;
x[a].sz.push_back(b);
x[b].sz.push_back(a);
}
for (i = 1; i <= n; ++i)
{
if (x[i].sz.size() == 1)
{
v.push_back(i);
zs.push_back(i);
szelessegi(i);
}
}
for (auto& e : zs)
{
if (x[e].lat)
{
ans.push_back(zs.front());
}
}
sort(ans.begin(), ans.end());
cout << ans.size() << "\n";
for (auto& e : ans)
{
cout << e << " ";
}
}
/*
6 5
1 2
2 3
3 4
4 5
5 6
*/
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// Debug program: F5 or Debug > Start Debugging menu
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