#include <bits/stdc++.h>
using namespace std;
const int MAX = 5e5;
int m, k, n, s, ar[MAX], b[MAX];
int cnt[MAX], cnt_b[MAX];
int main() {
  cin >> m >> k >> n >> s;
  for (int i = 0; i < m; i++) {
    cin >> ar[i];
    ar[i]--;
  }
  for (int i = 0; i < s; i++) {
    cin >> b[i];
    b[i]--;
    cnt_b[b[i]]++;
  }
  int matching = 0;
  int extra = m - n * k;
  int l = 0, r = k + extra - 1;
  for (int i = 0; i <= r; i++) {
    cnt[ar[i]]++;
    if (cnt[ar[i]] <= cnt_b[ar[i]]) matching++;
  }
  while (l < m) {
    if (l % k == 0 && r - l + 1 >= k && matching >= s) {
      vector<int> ans;
      for (int i = l; i <= r; i++) {
        if (cnt_b[ar[i]] > 0)
          cnt_b[ar[i]]--;
        else if (r - l + 1 - ans.size() > k)
          ans.push_back(i);
      }
      cout << ans.size() << "\n";
      for (int a : ans) cout << a + 1 << " ";
      return 0;
    }
    cnt[ar[l]]--;
    if (cnt[ar[l]] < cnt_b[ar[l]]) matching--;
    l++;
    if (r < m - 1) {
      r++;
      cnt[ar[r]]++;
      if (cnt[ar[r]] <= cnt_b[ar[r]]) matching++;
    }
  }
  cout << -1 << "\n";
}
