#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int m, k, n, s;
  cin >> m >> k >> n >> s;
  vector<int> A(m);
  vector<int> B(s);
  for (int i = 0; i < m; i++) {
    cin >> A[i];
  }
  vector<int> cnt(5e5 + 1);
  vector<int> cnt1(5e5 + 1);
  int allcnt = 0;
  for (int i = 0; i < s; i++) {
    cin >> B[i];
    cnt[B[i]]++;
  }
  for (int i = 0; i <= 5e5; i++) {
    if (cnt[i] != 0) {
      allcnt++;
    }
  }
  int j = 0;
  for (int i = 0; i < m; i++) {
    while (j < m && allcnt > 0) {
      cnt1[A[j]]++;
      if (cnt1[A[j]] == cnt[A[j]]) {
        allcnt--;
      }
      j++;
    }
    j--;
    if (allcnt > 0) {
      break;
    }
    int p = i / k + 1 + (m - j - 1) / k;
    if (p >= n) {
      int d = i % k;
      int l, r;
      int cntleft = min(i / k, n - 1);
      int cntright = n - 1 - cntleft;
      l = i - k * cntleft;
      r = max(j, i + k - 1) + cntright * k;
      vector<int> ans;
      for (int w = 0; w < l; w++) {
        ans.push_back(w + 1);
      }
      int k1 = k;
      k1 -= s;
      for (int w = i; w <= max(j, i + k - 1); w++) {
        if (cnt[A[w]] == 0 && k1 == 0) {
          ans.push_back(w + 1);
        } else if (cnt[A[w]] > 0) {
          cnt[A[w]]--;
        } else {
          k1--;
        }
      }
      for (int w = r + 1; w < m; w++) {
        ans.push_back(w + 1);
      }
      cout << ans.size() << "\n";
      for (int i = 0; i < ans.size(); i++) {
        cout << ans[i] << " ";
      }
      return 0;
    }
    if (cnt1[A[i]] == cnt[A[i]]) {
      allcnt++;
    }
    cnt1[A[i]]--;
    j++;
  }
  cout << -1;
  return 0;
}
