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import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;

public class mis {

	public static String solve(Reader in) throws IOException {
		final int cityCount = in.nextInt();
		final int roadCount = in.nextInt();
		final int minRoad = in.nextInt();
		
		Map<Integer, Set<Integer>> connections = new HashMap<>();
		for (int i=0; i<roadCount; i++) {
			int firstCity = in.nextInt();
			int secondCity = in.nextInt();
			Set<Integer> roadsFirst = connections.get(firstCity);
			if (roadsFirst == null) {
				connections.put(firstCity, roadsFirst = new HashSet<>());
			}
			roadsFirst.add(secondCity);
			Set<Integer> roadsSecond = connections.get(secondCity);
			if (roadsSecond == null) {
				connections.put(secondCity, roadsSecond = new HashSet<>());
			}
			roadsSecond.add(firstCity);
		}
		
		// remove all cities with not enough roads
		Stack<Integer> stack = new Stack<>();
		Set<Integer> used = new HashSet<>();
		for (Integer city: new HashSet<>(connections.keySet())) {
			Set<Integer> kids_city = connections.get(city);
			if (kids_city != null && kids_city.size() < minRoad) {
				stack.add(city);
				used.add(city);
				while (!stack.isEmpty()) {
					Integer cc = stack.pop();
					Set<Integer> kids_cc = connections.get(cc);
					connections.remove(cc);
					if (kids_cc != null) {
						for (Integer tt: kids_cc) {
							if (!used.contains(tt)) {
								Set<Integer> kids_tt = connections.get(tt);
								if (kids_tt != null) {
									kids_tt.remove(cc);
									if (kids_tt.size() < minRoad) {
										stack.push(tt);
									}
								}
							}
						}
					}
				}
			}
		}
		
		
		// decide on the biggest subset
		used = new HashSet<>();
		Set<Integer> bestSubset = new HashSet<>();
		
		stack = new Stack<>();
		
		for (Integer city: connections.keySet()) {
			if (!used.contains(city)) {
				Set<Integer> subset = new HashSet<>();
				
				stack.push(city);
				used.add(city);
				
				while (!stack.isEmpty()) {
					Integer cc = stack.pop();
					
					subset.add(cc);
					for (Integer tt: connections.get(cc)) {
						if (!used.contains(tt)) {
							stack.push(tt);
							used.add(tt);
						}
					}
				}
				
				if (subset.size() > bestSubset.size()) {
					bestSubset = subset;
				}
			}
		}
		
		
		if (bestSubset.size() == 0) {
			return "NIE\n";
		}
		
		StringBuilder sb = new StringBuilder();
		sb.append(bestSubset.size()).append("\n");
		List<Integer> bb = new ArrayList<>(bestSubset);
		Collections.sort(bb);
		
		for (Integer city: bb) {
			sb.append(city).append(" ");
		}
		sb.append("\n");
		return sb.toString();
	}
	
	
	
	public static void main(String[] args) throws IOException {
		Reader reader = new Reader(System.in);
		Writer writer = new Writer(System.out);
		String solution = solve(reader); 
		writer.println(solution);
		writer.flush();

	}

	/** Class for buffered reading int, long and double values */
	public static class Reader {
		BufferedReader reader;
		StringTokenizer tokenizer;

		public Reader(InputStream input) {
			reader = new BufferedReader(new InputStreamReader(input));
			tokenizer = new StringTokenizer("");
		}

		/** get next word */
		String next() throws IOException {
			while (!tokenizer.hasMoreTokens()) {
				String str = reader.readLine();
				if (str == null) {
					return null;
				}
				tokenizer = new StringTokenizer(str);
			}
			return tokenizer.nextToken();
		}

		int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}
		
		long nextLong() throws IOException {
			return Long.parseLong(next());
		}
	}

	/** Class for buffered writing int and double values */
	public static class Writer {
		BufferedWriter writer;

		public Writer(OutputStream out) {
			writer = new BufferedWriter(new OutputStreamWriter(out), 512);
		}
		
		void print(char c) throws IOException {
			writer.write(c);
		}

		void print(String str) throws IOException {
			writer.write(str);
		}

		void println(String str) throws IOException {
			writer.write(str);
			writer.write("\n");
		}

		void println() throws IOException {
			writer.write("\n");
		}

		void flush() throws IOException {
			writer.flush();
		}

		@Override
		protected void finalize() {
			try {
				writer.flush();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

}