#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long m, k, n, s;
  cin >> m >> k >> n >> s;
  long a[m];
  for (long i = 0; i < m; i++) {
    cin >> a[i];
  }
  long b[s], cnt[500001], cnt1[500001];
  memset(cnt, 0, sizeof(cnt));
  memset(cnt1, 0, sizeof(cnt1));
  for (long i = 0; i < s; i++) {
    cin >> b[i];
    cnt[b[i]]++;
  }
  long x = m - n * k;
  for (long i = 0; i < k + x; i++) {
    cnt1[a[i]]++;
  }
  bool fp = true;
  for (long i = 0; i < s; i++) {
    if (cnt1[b[i]] < cnt[b[i]]) {
      fp = false;
      break;
    }
  }
  long lo = -1, hi = -1, d = x, lo1, hi1;
  if (!fp) {
    lo1 = 0;
    fp = true;
    for (long i = 1; i <= (n - 1) * k; i++) {
      hi1 = i + k + x - 1;
      cnt1[a[lo1]]--;
      cnt1[a[hi1]]++;
      if (i % k == 0) {
        fp = true;
        for (long i = 0; i < s; i++) {
          if (cnt1[b[i]] < cnt[b[i]]) {
            fp = false;
            break;
          }
        }
        if (fp) {
          lo = lo1;
          hi = hi1;
          break;
        }
      }
      lo1++;
    }
  } else {
    lo = 0;
    hi = k + x - 1;
  }
  vector<long> pos;
  if (lo != -1) {
    for (long i = lo; i <= hi; i++) {
      if (cnt[a[i]] <= 0)
        pos.push_back(i + 1);
      else
        cnt[a[i]]--;
      if (pos.size() >= d) break;
    }
    cout << d << endl;
    for (long i = 0; i < d; i++) cout << pos[i] << " ";
    cout << endl;
  } else
    cout << -1 << endl;
}
