#include <bits/stdc++.h>
using namespace std;
using namespace chrono;
const int infinity = (int)1e9 + 42;
const int64_t llInfinity = (int64_t)1e18 + 256;
const int module = (int)1e9 + 7;
const long double eps = 1e-8;
mt19937_64 randGen(system_clock().now().time_since_epoch().count());
inline void raiseError(string errorCode) {
  cerr << "Error : " << errorCode << endl;
  exit(42);
}
signed main() {
  ios_base::sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  vector<vector<int> > g(n);
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  vector<int> d(n, INT_MAX);
  vector<int> p(n, -1);
  queue<int> q;
  q.push(0);
  d[0] = 0;
  while (!q.empty()) {
    int v = q.front();
    q.pop();
    for (int to : g[v]) {
      if (d[to] == INT_MAX) {
        d[to] = d[v] + 1;
        p[to] = v;
        q.push(to);
      }
    }
  }
  int ans1 = d[n - 1];
  int idx2 = -1;
  for (int i = 0; i < n; i++) {
    if (d[i] == 2) {
      idx2 = i;
      break;
    }
  }
  if (ans1 > 4 && idx2 >= 0) {
    cout << 4 << endl;
    cout << 1 << " " << p[idx2] + 1 << " " << idx2 + 1 << " " << 1 << " " << n
         << endl;
    return 0;
  }
  if (ans1 > 5) {
    vector<char> used(n, false);
    vector<vector<int> > komps;
    vector<int> kompId(n, -1);
    used[0] = true;
    function<void(int)> dfs = [&](int v) {
      if (used[v]) {
        return;
      }
      used[v] = true;
      kompId[v] = (int)komps.size() - 1;
      komps.back().push_back(v);
      for (int to : g[v]) {
        dfs(to);
      }
    };
    for (int i : g[0]) {
      if (!used[i]) {
        komps.emplace_back();
        dfs(i);
      }
    }
    for (int i = 0; i < n; i++) {
      sort(g[i].begin(), g[i].end());
    }
    for (auto &komp : komps) {
      sort(komp.begin(), komp.end());
      bool klika = true;
      int ngsz = (int)komp.size();
      int x = -1, y = -1;
      for (int i : komp) {
        if ((int)g[i].size() == ngsz) {
          continue;
        }
        for (int j : komp) {
          if (i == j) {
            continue;
          }
          if (!binary_search(g[i].begin(), g[i].end(), j)) {
            x = i;
            y = j;
            break;
          }
        }
        if (x < 0 || y < 0) {
          for (;;)
            ;
        }
        klika = false;
        break;
      }
      if (klika) {
        continue;
      }
      int z = -1;
      vector<int> xReach;
      for (int i = 1; i < n; i++) {
        if (i == x || i == y) {
          continue;
        }
        bool findX = binary_search(g[i].begin(), g[i].end(), x);
        bool findY = binary_search(g[i].begin(), g[i].end(), y);
        if (findX && findY) {
          z = i;
          break;
        } else if (findX) {
          xReach.push_back(i);
        }
      }
      if (z < 0) {
        z = -1;
        for (int i : xReach) {
          for (int j : g[i]) {
            if (j == x || j == 0 ||
                binary_search(xReach.begin(), xReach.end(), j)) {
              continue;
            }
            y = j;
            z = i;
            break;
          }
          if (z >= 0) {
            break;
          }
        }
        assert(z >= 0);
      }
      cout << 5 << endl;
      cout << 1 << " " << x + 1 << " " << z + 1 << " " << y + 1 << " " << x + 1
           << " " << n << endl;
      return 0;
    }
  }
  if (ans1 == INT_MAX) {
    cout << -1 << endl;
    return 0;
  }
  cout << ans1 << endl;
  vector<int> res;
  int kur = n - 1;
  while (kur >= 0) {
    res.push_back(kur + 1);
    kur = p[kur];
  }
  reverse(res.begin(), res.end());
  for (int i : res) {
    cout << i << " ";
  }
  cout << endl;
  return 0;
}
