import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class A {
    static int N;
    static int M;
    static int v;
    static int graph[][];
    static ArrayList depth[];
    static int used[];

    public static void BFS(int k, int v) {
        used[v - 1] = 1;
        for (int j = 0; j < depth[k].size(); j++) {
            for (int i = 0; i < N; i++) {
                if (graph[(int) depth[k].get(j) - 1][i] == 1) {
                    if (used[i] != 1) {
                        used[i] = 1;
                        depth[k + 1].add(i + 1);
                    }
                }
            }
        }
        if (k != N - 1) {
            for (int i = 0; i < depth[k+1].size(); i++) {
                BFS(k + 1, depth[k].get(i));
            }
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        N = sc.nextInt();
        M = sc.nextInt();
        v = sc.nextInt();
        //p = new int[N];
        graph = new int[N][N];
        for (int i = 0; i < M; i++) {
            int a = sc.nextInt();
            int b = sc.nextInt();
            graph[a - 1][b - 1] = 1;
            graph[b - 1][a - 1] = 1;
        }
        depth = new ArrayList<int>()[N];
        depth[0] = new ArrayList();
        used = new int[N];
        depth[0].add(v);
        BFS(0, v);
        int places = 0;
        for (int i = 0; i < N; i++) {
            if (used[i] == 1) {
                places = places + 1;
            }
        }
        System.out.println(places);
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < depth[i].size(); j++) {
                System.out.print(depth[i].get(j) + " ");
            }
        }

    }

}