#include <bits/stdc++.h>
using namespace std;
void solve() {
  int m, bsz, n, tsz;
  cin >> m >> bsz >> n >> tsz;
  int M = 0;
  vector<int> a(m);
  for (auto& x : a) {
    cin >> x;
    M = max(M, x);
  }
  auto gg = []() {
    cout << -1;
    exit(0);
  };
  vector<int> t(M + 1);
  for (int _ = 0; _ < tsz; _++) {
    int x;
    cin >> x;
    if (x > M) gg();
    t[x]++;
  }
  vector<int> b(M + 1);
  int l = 0, r = 0;
  int fullfill = 0;
  while (l < m) {
    while (r < m && (r - l < bsz || fullfill < tsz)) {
      int x = a[r++];
      if (++b[x] <= t[x]) fullfill++;
    }
    if (fullfill == tsz && r - l >= bsz &&
        min(l / bsz, n - 1) + (m - r) / bsz >= n - 1) {
      int cl = min(l / bsz, n - 1);
      vector<int> res;
      for (int i = cl * bsz; i < l; i++) {
        res.push_back(i);
      }
      for (int i = l, del = 0; i < r && del + bsz < r - l; i++) {
        int x = a[i];
        if (b[x] > t[x]) {
          b[x]--;
          del++;
          res.push_back(i);
        }
      }
      cout << res.size() << "\n";
      for (auto& x : res) {
        cout << x + 1 << ' ';
      }
      return;
    }
    int x = a[l++];
    if (b[x]-- <= t[x]) fullfill--;
  }
  gg();
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
  return 0;
}
