#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int m, k, n, s;
  cin >> m >> k >> n >> s;
  int len = m - k * (n - 1);
  vector<int> a(m);
  for (auto& i : a) {
    cin >> i;
  }
  int bad = 0;
  vector<int> cnt(5e5 + 1);
  for (int i = 0; i < s; ++i) {
    int b;
    cin >> b;
    bad += !cnt[b];
    ++cnt[b];
  }
  bool ok = false;
  vector<int> ans;
  for (int i = 0; i < m; ++i) {
    --cnt[a[i]];
    bad -= !cnt[a[i]];
    int j = i - len + 1;
    if (j >= 0) {
      if (!bad && j % k == 0) {
        for (int l = j; len - int(ans.size()) > k; ++l) {
          if (cnt[a[l]] < 0) {
            ans.push_back(l);
            ++cnt[a[l]];
          }
        }
        ok = true;
        break;
      }
      bad += !cnt[a[j]];
      ++cnt[a[j]];
    }
  }
  if (!ok) {
    cout << -1 << "\n";
  } else {
    cout << ans.size() << "\n";
    for (auto i : ans) {
      cout << i + 1 << " ";
    }
  }
}
