#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, s;
  cin >> n >> s;
  vector<int> v(n);
  map<int, int> kompr;
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    kompr[v[i]] = 42;
  }
  int k = 0;
  for (auto &it : kompr) {
    it.second = k++;
  }
  for (int i = 0; i < n; i++) {
    v[i] = kompr[v[i]];
  }
  auto w = v;
  sort(w.begin(), w.end());
  vector<vector<int> > g(k);
  map<pair<int, int>, vector<int> > indices;
  for (int i = 0; i < n; i++) {
    if (w[i] == v[i]) {
      continue;
    }
    s--;
    g[w[i]].push_back(v[i]);
    indices[{w[i], v[i]}].push_back(i);
  }
  if (s < 0) {
    cout << -1 << "\n";
    return 0;
  }
  vector<int> pass;
  function<void(int)> dfs = [&](int v) {
    while (!g[v].empty()) {
      int to = g[v].back();
      g[v].pop_back();
      dfs(to);
    }
    pass.push_back(v);
  };
  vector<vector<int> > ans;
  for (int i = 0; i < k; i++) {
    if (g[i].empty()) {
      continue;
    }
    pass.clear();
    dfs(i);
    ans.emplace_back();
    for (int j = 1; j < (int)pass.size(); j++) {
      auto &vec = indices[{pass[j], pass[j - 1]}];
      assert(!vec.empty());
      ans.back().push_back(vec.back());
      vec.pop_back();
    }
    reverse(ans.back().begin(), ans.back().end());
  }
  int canUnite = min(s, (int)ans.size());
  if (canUnite > 2) {
    vector<int> united;
    vector<int> loop2;
    for (int i = 0; i < canUnite; i++) {
      united.insert(united.end(), ans.back().begin(), ans.back().end());
      loop2.push_back(ans.back()[0]);
      ans.pop_back();
    }
    ans.push_back(united);
    reverse(loop2.begin(), loop2.end());
    ans.push_back(loop2);
  }
  cout << ans.size() << "\n";
  for (auto vec : ans) {
    cout << vec.size() << "\n";
    for (auto it : vec) {
      cout << it + 1 << " ";
    }
    cout << "\n";
  }
  return 0;
}
