#include <bits/stdc++.h>
using namespace std;
vector<string> vec_splitter(string s) {
  for (char &c : s) c = c == ',' ? ' ' : c;
  stringstream ss;
  ss << s;
  vector<string> res;
  for (string z; ss >> z; res.push_back(z))
    ;
  return res;
}
void debug_out(vector<string> args, int idx) { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(vector<string> args, int idx, Head H, Tail... T) {
  if (idx > 0) cerr << ", ";
  stringstream ss;
  ss << H;
  cerr << args[idx] << " = " << ss.str();
  debug_out(args, idx + 1, T...);
}
void localTest() {}
vector<long long> A, B;
long long m, k, n, s, mxDel, cnt;
map<long long, long long> has;
void del(long long x) {
  if (!has[x]) {
    ++cnt;
  }
  --has[x];
  return;
}
void add(long long x) {
  ++has[x];
  if (!has[x]) {
    --cnt;
  }
  return;
}
int main() {
  localTest();
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> m >> k >> n >> s;
  A.resize(m);
  B.resize(s);
  for (auto &x : A) {
    cin >> x;
  }
  for (auto &x : B) {
    cin >> x;
    del(x);
  }
  for (long long i = 0, j = 0; i < m; ++i) {
    while (j < m && (cnt != 0 || j - i < k)) {
      add(A[j]);
      j++;
    }
    if (cnt != 0) {
      break;
    }
    if (j - i >= k && i / k + 1 + (m - j) / k >= n) {
      long long rem = j - i - k;
      cout << rem << "\n";
      for (long long l = i; l < j && rem > 0; ++l) {
        if (has[A[l]]) {
          has[A[l]]--;
          cout << l + 1 << " ";
          rem--;
        }
      }
      cout << "\n";
      return 0;
    }
    del(A[i]);
  }
  cout << "-1\n";
  return 0;
}
