#include <bits/stdc++.h>
using namespace std;
using namespace std;
const int maxn = 5e5 + 10;
int a[maxn];
int need[maxn] = {0};
int cnt[maxn] = {0};
int ans[maxn] = {0};
bool vis[maxn] = {0};
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, k, m, s;
  cin >> n >> k >> m >> s;
  for (int i = 1; i <= n; i++) cin >> a[i];
  int len = n - k * m + k;
  int del = n - k * m;
  int kinds = 0;
  for (int i = 1; i <= s; i++) {
    int temp;
    cin >> temp;
    if (!need[temp]) {
      vis[temp] = 1;
      kinds++;
    }
    ++need[temp];
  }
  bool flag = 0;
  int L = 1;
  for (int i = 1; i <= len; i++) {
    int temp = a[i];
    cnt[temp]++;
    if (vis[temp] && cnt[temp] == need[temp]) kinds--;
    if (kinds == 0) {
      L = 1;
      flag = 1;
      break;
    }
  }
  if (!flag)
    for (int i = len + 1; i <= n; i++) {
      int l = a[L];
      int r = a[i];
      L++;
      cnt[l]--;
      if (vis[l]) {
        if (cnt[l] == need[l] - 1) kinds++;
      }
      cnt[r]++;
      if (vis[r]) {
        if (cnt[r] == need[r]) kinds--;
      }
      if (kinds == 0 && (L - 1) % k == 0) {
        flag = 1;
        break;
      }
    }
  int num = 0;
  if (flag) {
    for (int i = L; i < len + L; i++) {
      int temp = a[i];
      if (need[temp] > 0) {
        need[temp]--;
        continue;
      }
      if (num == del) break;
      ans[++num] = i;
    }
    cout << num << endl;
    for (int i = 1; i <= num; i++) {
      if (i != num)
        cout << ans[i] << ' ';
      else
        cout << ans[num] << endl;
    }
  } else
    cout << -1 << endl;
  return 0;
}
