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//package com.company;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.lang.Integer;
import java.util.*;

/**
 * Kornel
 * PA2015/2B/MIS
 */
public class mis {

    private static final int MAX = 200005;

    private static int N;
    private static int M;
    private static int D;
    private static City[] city = new City[MAX];
    public static final String NO_WAY = "NIE";

    public static void main(String[] args) throws IOException {
        long time = System.currentTimeMillis();

        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out);

        String[] res = in.readLine().split(" ");
        N = Integer.valueOf(res[0]);
        M = Integer.valueOf(res[1]);
        D = Integer.valueOf(res[2]);

        int from;
        int to;
        for (int i = 1; i <= M; i++) {
            res = in.readLine().split(" ");
            from = Integer.valueOf(res[0]);
            to = Integer.valueOf(res[1]);
            if (city[from] == null) {
                city[from] = new City(from);
            }
            if (city[to] == null) {
                city[to] = new City(to);
            }
            city[from].connected.add(to);
            city[to].connected.add(from);
        }

        List<City> list = new LinkedList<>();
        for (int i = 0; i < MAX; i++) {
            if (city[i] != null) {
                list.add(city[i]);
            }
        }
        City c;
        int size;
        while (true) {
            size = list.size();
            Iterator<City> iter = list.iterator();
            while (iter.hasNext()) {
                c = iter.next();
                if (c.connected.size() < D) {
                    c.remove();
                    iter.remove();
                }
            }
            if (size == list.size()) {
                break;
            }
        }

        int maxGroup = 0;
        int maxGroupSize = 0;
        int group = 1;
        int groupSize;
        Iterator<City> iter = list.iterator();
        while (iter.hasNext()) {
            c = iter.next();
            groupSize = bfs(c.id, group);
            if (groupSize > maxGroupSize) {
                maxGroupSize = groupSize;
                maxGroup = group;
            }
            group++;
        }


        if (size == 0) {
            out.println(NO_WAY);
        } else {
            out.println(maxGroupSize);
            iter = list.iterator();
            while (iter.hasNext()) {
                c = iter.next();
                if (c.group == maxGroup) {
                    out.print(c.id + " ");
                }
            }
        }

        out.flush();
    }

    public static int bfs(int startFrom, int group) {
        if (city[startFrom].group != 0) {
            return -1;
        }

        int groupSize = 0;
        Queue<Integer> queue = new LinkedList<>();
        queue.add(startFrom);
        city[startFrom].visited = true;
        city[startFrom].group = group;
        groupSize++;
        while(!queue.isEmpty()) {
            Integer parent = queue.remove();

            int size = city[parent].connected.size();
            for (int i = 0; i < size; i++) {
                Integer child = city[parent].connected.get(i);
                if (!city[child].visited) {
                    city[child].visited = true;
                    city[child].group = group;
                    groupSize++;
                    queue.add(child);
                }
            }
        }

        return groupSize;
    }

    static class City {
        List<Integer> connected = new ArrayList<>();
        boolean isRemoved;
        boolean visited;
        int id;
        int group;

        public City(int id) {
            this.id = id;
        }

        public void remove() {
            isRemoved = true;
            for (int i = 0; i < connected.size(); i++) {
                int index = city[connected.get(i)].connected.indexOf(id);
                if (index != -1) {
                    city[connected.get(i)].connected.remove(index);
                }
            }
        }
    }
}