#include <bits/stdc++.h>
using namespace std;
vector<int> se[2050];
int n, m, tot;
int head[2050];
struct node {
  int to, next;
} edge[2100000];
struct node1 {
  int a, b;
} p, Q[2050 * 2050];
int mat[2050][2050], pre[2050 * 2050];
int main() {
  int i, j, cas, a, b;
  while (scanf("%d%d", &n, &m) != EOF) {
    for (i = 0; i <= n; i++) {
      for (j = 0; j <= n; j++) {
        mat[i][j] = -1;
      }
    }
    for (i = 0; i <= n; i++) se[i].clear();
    for (i = 0; i < m; i++) {
      scanf("%d%d", &a, &b);
      se[a].push_back(b);
      se[b].push_back(a);
    }
    int L = 1, h = 1, y, yy;
    a = 1;
    b = n;
    Q[h].a = a;
    Q[h].b = b;
    pre[0] = 0;
    mat[1][n] = 0;
    int ans = -1;
    while (L <= h) {
      a = Q[L].a;
      b = Q[L].b;
      for (i = 0; i < se[a].size(); i++) {
        y = se[a][i];
        for (j = 0; j < se[b].size(); j++) {
          yy = se[b][j];
          if (y != yy && mat[y][yy] == -1) {
            h++;
            mat[y][yy] = mat[a][b] + 1;
            Q[h].a = y;
            Q[h].b = yy;
            pre[h] = L;
            if (y == n && yy == 1) {
              ans = h;
            }
          }
        }
      }
      if (ans != -1) break;
      L++;
    }
    if (mat[n][1] == -1) {
      printf("-1\n");
      continue;
    }
    printf("%d\n", mat[n][1]);
    int now = ans;
    while (now > 1) {
      printf("%d ", Q[now].b);
      now = pre[now];
    }
    printf("%d\n", Q[now].b);
    now = ans;
    while (now > 1) {
      printf("%d ", Q[now].a);
      now = pre[now];
    }
    printf("%d\n", Q[now].a);
  }
  return 0;
}
