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import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

class Graph {
    private Map<Integer, Set<Integer>> adj;

    public Graph(int n) {
        adj = new LinkedHashMap<>();
        for (int i = 1; i <= n; i++) {
            adj.put(i, new HashSet<>());
        }
    }

    public void insertEdge(int a, int b) {
        adj.get(a).add(b);
        adj.get(b).add(a);
    }

    public int getDegree(int a) {
        return adj.get(a).size();
    }

    public void removeNodes(Queue<Integer> nodesToRemove, int d) {
        while (!nodesToRemove.isEmpty()) {
            int node = nodesToRemove.poll();
            if (adj.containsKey(node)) {
                for (int neighbour : adj.get(node)) {
                    adj.get(neighbour).remove(node);
                    if (getDegree(neighbour) < d) {
                        nodesToRemove.add(neighbour);
                    }
                }
                adj.remove(node);
            }
        }
    }

    public Set<Integer> getLargestComponent() {
        Map<Integer, Boolean> visited = new HashMap<>();
        for (int node : adj.keySet()) {
            visited.put(node, false);
        }
        Set<Integer> largestComponent = new TreeSet<>();
        for (int node : adj.keySet()) {
            Set<Integer> component = new TreeSet<>();
            if (!visited.get(node)) {
                visit(node, visited, component);
            }
            if (component.size() > largestComponent.size()) {
                largestComponent = component;
            }
        }
        return largestComponent;
    }

    private void visit(int node, Map<Integer, Boolean> visited, Set<Integer> component) {
        visited.put(node, true);
        component.add(node);
        for (int neighbour : adj.get(node)) {
            if (!visited.get(neighbour)) {
                visit(neighbour, visited, component);
            }
        }
    }
}

public class mis {

    public static void main(String[] args) {
        Scanner SC = new Scanner(System.in);
        int n = SC.nextInt();
        int m = SC.nextInt();
        int d = SC.nextInt();
        Graph G = new Graph(n);
        for (int i = 0; i < m; i++) {
            int a = SC.nextInt();
            int b = SC.nextInt();
            G.insertEdge(a, b);
        }
        Queue<Integer> nodesToRemove = getInitialNodesToDelete(G, n, d);
        G.removeNodes(nodesToRemove, d);
        Set<Integer> largestComponent = G.getLargestComponent();
        if (largestComponent.isEmpty()) {
            System.out.println("NIE");
        } else {
            System.out.println(largestComponent.size());
            for (Integer node : largestComponent) {
                System.out.print(node + " ");
            }
            System.out.println();
        }
    }

    private static Queue<Integer> getInitialNodesToDelete(Graph G, int n, int d) {
        Queue<Integer> initialNodesToDelete = new LinkedList<>();
        for (int i = 1; i <= n; i++) {
            if (G.getDegree(i) < d) {
                initialNodesToDelete.add(i);
            }
        }
        return initialNodesToDelete;
    }

}