#include <bits/stdc++.h>
using namespace std;
template <class T>
int getbit(T s, int i) {
  return (s >> i) & 1;
}
template <class T>
T onbit(T s, int i) {
  return s | (T(1) << i);
}
template <class T>
T offbit(T s, int i) {
  return s & (~(T(1) << i));
}
template <class T>
int cntbit(T s) {
  return __builtin_popcount(s);
}
template <class T>
T gcd(T a, T b) {
  T r;
  while (b != 0) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
int n, k, m, s;
int a[1000005], need[1000005], cur[1000005];
void solve() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> k >> m >> s;
  for (int i = (1); i <= (n); ++i) cin >> a[i];
  memset(need, 0, sizeof(need));
  memset(cur, 0, sizeof(cur));
  for (int i = (1); i <= (s); ++i) {
    int x;
    cin >> x;
    need[x]++;
  }
  int dem = 0;
  for (int i = (1); i <= (1000005 - 1); ++i)
    if (need[i]) dem++;
  int cuoi = 1;
  for (int i = (1); i <= (n); ++i) {
    cur[a[i]]++;
    if (cur[a[i]] == need[a[i]]) dem--;
    if (dem == 0 && i >= k) {
      cuoi = i;
      break;
    }
  }
  if (dem > 0) {
    cout << -1 << endl;
    return;
  }
  for (int i = (1); i <= (n); ++i) {
    if (i != 1) {
      cur[a[i - 1]]--;
      if (cur[a[i - 1]] < need[a[i - 1]]) {
        while (cuoi <= n &&
               (cur[a[i - 1]] < need[a[i - 1]] || cuoi - i + 1 < k)) {
          cuoi++;
          cur[a[cuoi]]++;
        }
        if (cuoi == n + 1) break;
      }
    }
    if ((i - 1) / k + 1 + (n - cuoi) / k >= m) {
      vector<int> res;
      for (int j = (1); j <= ((i - 1) % k); ++j) res.push_back(j);
      int num = cuoi - i + 1;
      for (int j = (i); j <= (cuoi); ++j) {
        if (num > k && cur[a[j]] > need[a[j]]) {
          cur[a[j]]--;
          num--;
          res.push_back(j);
        }
      }
      for (int j = (n - (n - cuoi) % k + 1); j <= (n); ++j) res.push_back(j);
      cout << ((int)(res).size()) << endl;
      for (int j = 0; j < (((int)(res).size())); ++j) cout << res[j] << " ";
      return;
    }
  }
  cout << -1 << endl;
}
int main() {
  solve();
  return 0;
}
