#include <bits/stdc++.h>
using namespace std;
const int maxn = 6e6 + 10;
int a[maxn], b[maxn], c[maxn];
int vis[maxn];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int m, n, s, k;
  cin >> m >> k >> n >> s;
  for (int i = 1; i <= m; i++) cin >> a[i];
  int m1 = 0;
  for (int i = 1; i <= s; i++) {
    cin >> b[i], c[b[i]]++;
    m1 = max(m1, b[i]);
  }
  int cnt1 = 0;
  for (int i = 1; i <= m1; i++) {
    if (c[i]) vis[i] = 1, cnt1++;
  }
  int cc = m - n * k, cnt = 0;
  for (int i = 1; i <= k + cc; i++) {
    c[a[i]]--;
    if (vis[a[i]] && c[a[i]] == 0) {
      cnt++;
    }
  }
  int id = -1;
  if (cnt == cnt1) {
    cout << cc << endl;
    memset(c, 0, sizeof(c));
    for (int i = 1; i <= s; i++) {
      c[b[i]]++;
    }
    int ccc = 0;
    for (int i = 1; i <= k + cc; i++) {
      c[a[i]]--;
      if (ccc == cc) break;
      if (vis[a[i]] == 0) {
        ccc++;
        cout << i << " ";
        continue;
      }
      if (c[a[i]] < 0) {
        cout << i << " ";
        ccc++;
      }
    }
    cout << endl;
    return 0;
  }
  for (int i = k + cc + 1; i <= m; i++) {
    c[a[i]]--;
    if (vis[a[i]] && c[a[i]] == 0) cnt++;
    c[a[i - k - cc]]++;
    if (vis[a[i - k - cc]] && c[a[i - k - cc]] == 1) cnt--;
    if ((i - k - cc) % k != 0) continue;
    if (cnt == cnt1) {
      id = i;
      break;
    }
  }
  if (id == -1) {
    cout << "-1" << endl;
  } else {
    vector<int> v;
    memset(c, 0, sizeof(c));
    for (int i = 1; i <= s; i++) {
      c[b[i]]++;
    }
    int ccc = 0;
    for (int i = id - k - cc + 1; i <= min(id, m); i++) {
      c[a[i]]--;
      if (ccc == cc) break;
      if (vis[a[i]] == 0) {
        ccc++;
        v.push_back(i);
        continue;
      }
      if (c[a[i]] < 0) {
        v.push_back(i);
        ccc++;
      }
    }
    cout << v.size() << endl;
    for (int i = 0; i < v.size(); i++) cout << v[i] << " ";
    cout << endl;
  }
  return 0;
}
