#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, k, m, s;
  cin >> m >> k >> n >> s;
  vector<int> v(m), b(s);
  map<int, int> ma;
  for (int i = 0; i < m; i++) cin >> v[i];
  for (int i = 0; i < s; i++) {
    cin >> b[i];
    ma[b[i]]++;
  }
  int remov = m - n * k;
  vector<int> cnt(500010, 0);
  vector<int> ans;
  for (int i = 0; i < m; i++) {
    if (i >= k + remov) cnt[v[i - (k + remov)]]--;
    cnt[v[i]]++;
    if (i + 1 >= k + remov) {
      if ((i + 1 - k - remov) % k != 0) continue;
      bool flag = true;
      for (auto it : ma) {
        if (cnt[it.first] < it.second) {
          flag = false;
          break;
        }
      }
      if (!flag) continue;
      for (int j = i - (k + remov) + 1; j <= i; j++) {
        if (remov == 0) break;
        if (ma[v[j]] > 0)
          ma[v[j]]--;
        else {
          ans.push_back(j + 1);
          remov--;
        }
      }
      sort(ans.begin(), ans.end());
      cout << ans.size() << endl;
      if (!ans.empty()) {
        for (int i = 0; i < ans.size(); i++) {
          if (i) cout << " ";
          cout << ans[i];
        }
        cout << endl;
      }
      return 0;
    }
  }
  cout << -1 << endl;
  return 0;
}
