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#include <iostream>
#include <vector>
#include <unordered_set>
#include <set>

using namespace std;

int main() {
	std::ios_base::sync_with_stdio (false);
//	cin.tie(NULL);
	
	int n, m, d;
	cin >> n;
	cin >> m;
	cin >> d;

	vector<unordered_set<int> > g(n+1);
	unordered_set<int> vg;
	int s, e;
	for (int i = 0; i < m; ++i) {
		cin >> s;
		cin >> e;
		vg.insert(s);
		vg.insert(e);
		//cout << "inserting " << s << " " << e << endl;
		g[s].insert(e);
		if (s != e)
			g[e].insert(s);
	}
	
	// clear the data
	bool bad_found = true;
	unordered_set<int> cands;
	for (auto itvg = vg.begin(); itvg != vg.end(); ++itvg) {
		int i = *itvg;
		if (g[i].size() < d)
			cands.insert(i);
	}	

	while (cands.size() > 0) {
		int i = *(cands.begin());
		cands.erase(cands.begin());
		unordered_set<int>::iterator it;
		for (it = g[i].begin(); it != g[i].end(); ++it) {
			g[*it].erase(i);
			if (g[*it].size() < d)
				cands.insert(*it);
		}
	}

	//cout << endl;
	for (int i = 1; i < n+1; ++i) {
	//	cout << g[i].size() << endl;
	}

	unordered_set<int> g2;

	for (int i = 1; i < n+1; ++i) {
		if (g[i].size() >= d)
			g2.insert(i);
	}

	vector<set<int> > sfor;

	if (g2.size() == 0) {
		cout << "NIE" << endl;
		return 0;
	}

	while (g2.size() > 0) {
		set<int> dfset;
		int st = *(g2.begin());
	//	cout << "dfs start " << st << endl;
		vector<int> S;
		S.push_back(st);
		while (S.size() > 0) {
			int v = S.back();
			S.pop_back();
			if (g2.find(v) != g2.end()) {
				g2.erase(v);
				dfset.insert(v);
				for (unordered_set<int>::iterator it = g[v].begin(); it != g[v].end(); ++it) {
					S.push_back(*it);
				}
			}
		}
			
		sfor.push_back(dfset);
	}

	int maxsfor = -1;
	int msforpos = 0;

	//cout << "debug sfor size " << sfor.size() << endl;

	for (int i = 0; i < sfor.size(); ++i) {
	//	cout << "sfor[i].size() " << sfor[i].size() << endl;
		int sforsize = sfor[i].size();
		if (sforsize > maxsfor) {
	//		cout << "max1 " << maxsfor << endl;
			maxsfor = sforsize;
	//		cout << "max2 " << maxsfor << endl;
			msforpos = i;
		} else {
	//		cout << "yyy? " << sfor[i].size() << " maxsfor " << maxsfor << " bool ? " << (sfor[i].size() > maxsfor) << " uu ? " << (3 > -1) << endl;
		}
	}

	cout << maxsfor << endl;
	int zz = 0;
	for (auto it = sfor[msforpos].begin(); it != sfor[msforpos].end(); ++it) {
		++zz;
		cout << *it;
		if (zz < maxsfor)
			cout << " ";
	}
	cout << endl;

	return 0;
}