#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 9;
const double eps = 1e-5;
const int maxN = 2e3 + 10;
const int inf = 1e9;
int n, m;
vector<pair<int, int> > a[maxN];
int vis[maxN], c[maxN];
vector<int> pat;
inline void dfs(int v, int f = -1) {
  for (int i = 0; i < a[v].size(); i++) {
    if (a[v][i].first <= f) continue;
    if (!vis[a[v][i].second]) {
      vis[a[v][i].second] = 1;
      dfs(a[v][i].first);
    }
  }
  pat.push_back(v);
}
inline void init() {
  cin >> n >> m;
  for (int i = 0; i < m + 1; i++) {
    cin >> c[i];
    c[i]--;
  }
  for (int i = 1; i < m + 1; i++) {
    int v = c[i - 1], u = c[i];
    a[v].push_back(make_pair(u, i - 1));
    a[u].push_back(make_pair(v, i - 1));
  }
  for (int i = 0; i < n; i++) sort(a[i].begin(), a[i].end());
}
inline void solve() {
  for (int i = m - 1; i >= 0; i--) {
    memset(vis, 0, sizeof vis);
    pat.clear();
    for (int j = 0; j < i; j++) vis[j] = 1;
    dfs(c[i], c[i + 1]);
    if (i + pat.size() == m + 1) {
      reverse(pat.begin(), pat.end());
      for (int j = 0; j < i; j++) cout << c[j] + 1 << " ";
      for (int j = 0; j < pat.size(); j++) cout << pat[j] + 1 << " ";
      cout << endl;
      return;
    }
  }
  cout << "No solution" << endl;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie();
  cout.tie();
  init();
  solve();
  return 0;
}
