#include <bits/stdc++.h>
using namespace std;
using cd = complex<double>;
const int Inf = 100000000;
const int mod = 998244353;
const double Pi = acos(-1);
void Fastio() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
}
int n, k, m, s, st = 0;
int cnt[500005], a[500005], r[500005], c[500005];
int main() {
  cin >> m >> k >> n >> s;
  for (int i = 1; i <= m; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= s; i++) {
    int temp;
    cin >> temp;
    cnt[temp]++;
  }
  s = 0;
  for (int i = 1; i <= 500000; i++) {
    if (cnt[i]) {
      s++;
    }
  }
  int temp = 0;
  for (int i = 1; i <= m; i++) {
    if (i != 1) {
      c[a[i - 1]]--;
      if (c[a[i - 1]] == cnt[a[i - 1]] - 1) {
        st--;
      }
    }
    while (temp != m + 1 and st != s) {
      temp++;
      c[a[temp]]++;
      if (c[a[temp]] == cnt[a[temp]]) {
        st++;
      }
    }
    r[i] = temp;
  }
  for (int i = 1; i <= 500000; i++) {
    c[i] = 0;
  }
  for (int i = 1; i <= m; i++) {
    if (r[i] == m + 1) {
      break;
    }
    int t = r[i] - i + 1;
    int temp = (i - 1) % k;
    if (t > k) {
      temp += (t - k);
    }
    if (m - temp >= n * k) {
      vector<int> Ans;
      for (int j = 1; j <= (i - 1) % k; j++) {
        Ans.emplace_back(j);
      }
      temp -= (i - 1) % k;
      for (int j = i; j <= r[i]; j++) {
        c[a[j]]++;
      }
      for (int j = i; j <= r[i]; j++) {
        if (cnt[a[j]] < c[a[j]] and temp > 0) {
          temp--;
          c[a[j]]--;
          Ans.emplace_back(j);
        }
      }
      cout << Ans.size() << '\n';
      for (auto x : Ans) {
        cout << x << ' ';
      }
      return 0;
    }
  }
  cout << -1;
}
