#include <bits/stdc++.h>
using namespace std;
const int maxn = 23, maxs = 1 << 22 | 1;
int n, m, all, e[maxn], g[maxn], dsu[maxn][maxn], ans, out;
int dsu_find(int dsu[], int x) {
  return dsu[x] < 0 ? x : dsu[x] = dsu_find(dsu, dsu[x]);
}
void dsu_merge(int dsu[], int u, int v) {
  u = dsu_find(dsu, u);
  v = dsu_find(dsu, v);
  if (u == v) return;
  if (dsu[u] < dsu[v]) swap(u, v);
  if (dsu[u] == dsu[v]) --dsu[v];
  dsu[u] = v;
}
void dfs(int dep, int sel, int cov) {
  if (dep == n) {
    if (cov < all) return;
    int cnt = 0;
    for (int i = 0, fir = -1; i < n; ++i) {
      if (!(sel & (1 << i))) continue;
      ++cnt;
      if (fir == -1)
        fir = i;
      else if (dsu_find(dsu[n], fir) != dsu_find(dsu[n], i))
        return;
    }
    if (cnt < ans) {
      ans = cnt;
      out = sel;
    }
    return;
  }
  memcpy(dsu[dep + 1], dsu[dep], n * sizeof(int));
  dfs(dep + 1, sel, cov);
  int adt = e[dep] & sel;
  for (int i = 0; i < n; ++i)
    if (adt & (1 << i)) dsu_merge(dsu[dep + 1], dep, i);
  dfs(dep + 1, sel | 1 << dep, cov | e[dep]);
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; ++i) e[i] |= 1 << i;
  for (int i = 0; i < m; ++i) {
    int u, v;
    scanf("%d%d", &u, &v);
    --u, --v;
    e[u] |= 1 << v;
    e[v] |= 1 << u;
  }
  if (m == n * (n - 1) / 2) {
    puts("0");
    return 0;
  }
  ans = n;
  out = all = (1 << n) - 1;
  memset(dsu[0], -1, n * sizeof(int));
  dfs(0, 0, 0);
  printf("%d\n", ans);
  for (int i = 0, fir = 1; i < n; ++i)
    if (out & (1 << i)) {
      if (fir)
        fir = 0;
      else
        putchar(' ');
      printf("%d", i + 1);
    }
  puts("");
  return 0;
}
