#include <bits/stdc++.h>
using namespace std;
int need[500000];
int have[500000];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int m, k, n, s;
  cin >> m >> k >> n >> s;
  int a[m];
  for (int i = 0; i < m; i++) {
    cin >> a[i];
    a[i]--;
  }
  int inf = 500000;
  for (int i = 0; i < inf; i++) {
    need[i] = 0;
    have[i] = 0;
  }
  int bad = 0;
  for (int i = 0; i < s; i++) {
    int x;
    cin >> x;
    x--;
    if (need[x] == 0) {
      bad++;
    }
    need[x]++;
  }
  int p1 = 0;
  int p2 = 0;
  if (need[a[0]] == 1) {
    bad--;
  }
  have[a[0]]++;
  for (int i = 0; i < m; i++) {
    while (p2 < i) {
      p2++;
      have[a[p2]]++;
      if (have[a[p2]] == need[a[p2]]) {
        bad--;
      }
    }
    while (p1 < i) {
      if (have[a[p1]] == need[a[p1]]) {
        bad++;
      }
      have[a[p1]]--;
      p1++;
    }
    while ((bad > 0 || p2 - p1 + 1 < k) && p2 + 1 < m) {
      p2++;
      have[a[p2]]++;
      if (have[a[p2]] == need[a[p2]]) {
        bad--;
      }
    }
    if (bad > 0 || p2 - p1 + 1 < k) {
      break;
    }
    int lose = (p1 % k) + ((m - p2 - 1) % k) + (p2 - p1 + 1 - k);
    if (lose + n * k <= m) {
      vector<int> li;
      int ext = k - s;
      for (int j = p1; j <= p2; j++) {
        if (need[a[j]] > 0) {
          need[a[j]]--;
        } else if (ext > 0) {
          ext--;
        } else {
          li.push_back(j + 1);
        }
      }
      cout << li.size() << endl;
      for (int j = 0; j < li.size(); j++) {
        cout << li[j] << " ";
      }
      cout << endl;
      return 0;
    }
  }
  cout << -1 << endl;
}
