#include <bits/stdc++.h>
using namespace std;
const long long N = 6e5 + 7, M = 1000000007, inf = INT_MAX;
const long long INF = LLONG_MAX;
long long n, Q, m, k, s;
long long arr[N + 2], freq[N], r[N];
bool vis[N];
void remove(long long i, long long &cnt) {
  freq[arr[i]]--;
  if (vis[arr[i]] and freq[arr[i]] < r[arr[i]]) {
    vis[arr[i]] = 0;
    cnt++;
  }
}
void solve() {
  cin >> m >> k >> n >> s;
  for (long long i = 0; i < (long long)m; i++) cin >> arr[i];
  long long mxrem = m - n * k;
  set<long long> st;
  for (long long i = 0; i < (long long)s; i++) {
    long long x;
    cin >> x;
    st.insert(x), r[x]++;
  }
  long long cnt = st.size();
  long long i = 0, j = 0, f = 1;
  long long b1 = -1, b2 = -1;
  while (i < m) {
    if (j < i) j = i;
    long long avail = mxrem - (i % k);
    if (avail < 0) {
      if (i < j) remove(i, cnt);
      i++;
    } else {
      while (j < m and cnt) {
        freq[arr[j]]++;
        if (!vis[arr[j]] and st.find(arr[j]) != st.end() and
            freq[arr[j]] >= r[arr[j]]) {
          vis[arr[j]] = 1;
          cnt--;
        }
        j++;
      }
      if (cnt)
        f = 0;
      else {
        long long torem = max(0ll, (j - i) - k);
        if (avail >= torem) {
          b1 = i, b2 = j - 1;
          break;
        } else
          remove(i, cnt);
        i++;
      }
    }
    if (!f) break;
  }
  if (!f)
    cout << -1 << '\n';
  else {
    for (auto &i : st) freq[i] = 0;
    for (long long j = b1; j < (long long)b2 + 1; j++) {
      if (st.find(arr[j]) != st.end()) freq[arr[j]]++;
    }
    long long torem = max(0ll, (j - i) - k);
    vector<long long> vec;
    for (long long i = 0; i < (long long)b1 % k; i++) vec.push_back(i);
    for (long long j = b1; j < (long long)b2 + 1; j++) {
      if (torem > 0 and
          (st.find(arr[j]) == st.end() or freq[arr[j]] > r[arr[j]])) {
        freq[arr[j]]--;
        vec.push_back(j), torem--;
      }
    }
    cout << vec.size() << '\n';
    for (auto i : vec) cout << i + 1 << " ";
    cout << '\n';
  }
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long test = 1;
  while (test--) solve();
}
