#include <bits/stdc++.h>
using namespace std;
template <class T>
using VV = vector<vector<T>>;
template <class T>
inline T SMIN(T& a, const T b) {
  return a = (a > b) ? b : a;
}
template <class T>
inline T SMAX(T& a, const T b) {
  return a = (a < b) ? b : a;
}
template <class Iter>
void __kumaerrc(Iter begin, Iter end) {
  for (; begin != end; ++begin) {
    cerr << *begin << ',';
  }
  cerr << endl;
}
void __kumaerr(istream_iterator<string> it) {
  (void)it;
  cerr << endl;
}
template <typename T, typename... Args>
void __kumaerr(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << "=" << a << ", ", __kumaerr(++it, args...);
}
template <typename S, typename T>
std::ostream& operator<<(std::ostream& _os, const std::pair<S, T>& _p) {
  return _os << "{" << _p.first << ',' << _p.second << "}";
}
const int MAX_N = 1e6 + 1;
long long A[MAX_N], B[MAX_N];
int M, K, N, S;
int BB[MAX_N];
void nope() {
  fprintf(stdout, "%d", -1), putchar('\n');
  ;
  exit(0);
}
void yup(vector<int>& res) {
  assert(M - int((res).size()) >= N * K);
  fprintf(stdout, "%d", int((res).size())), putchar('\n');
  ;
  for (int i = 0; i < (int((res).size())); ++i) printf("%d ", res[i] + 1);
  fprintf(stdout, ""), putchar('\n');
  ;
  exit(0);
}
int g(int l, int r) { return (r - l) / K; }
void f(int l, int r) {
  int mrem = r - l - K, ext = r - l - S;
  if (mrem > ext) return;
  int s = K - (r - l), ss = max(0, s);
  ;
  vector<int> res;
  auto remM = [&]() {
    vector<int> cur(M + 1, 0);
    for (int i = (l); i < (r); ++i) {
      int t = A[i];
      if (cur[t] < BB[t])
        cur[t]++;
      else if (mrem > 0)
        res.push_back(i), --mrem;
    }
  };
  int x = g(0, l - ss), y = g(r, M);
  if (x + y + 1 >= N) {
    ;
    remM();
    yup(res);
  }
  x = g(0, l), y = g(r + ss, M);
  if (x + y + 1 >= N) {
    ;
    remM();
    yup(res);
  }
}
void solve() {
  for (int i = 0; i < (S); ++i) BB[B[i]]++;
  int r = 0, cnt = 0;
  map<int, int> cur;
  for (int l = 0; l < (M); ++l) {
    while (r < M && cnt < S) {
      int t = A[r];
      cur[t]++;
      if (cur[t] <= BB[t]) ++cnt;
      ++r;
    };
    if (cnt == S) f(l, r);
    int t = A[l];
    if (cur[t] <= BB[t]) --cnt;
    cur[t]--;
  }
  nope();
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << setprecision(12) << fixed;
  cin >> M >> K >> N >> S;
  for (int i = 0; i < (M); ++i) cin >> A[i];
  for (int i = 0; i < (S); ++i) cin >> B[i];
  solve();
  return 0;
}
