#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int m, k, n, s;
  cin >> m >> k >> n >> s;
  vector<int> a(m);
  int mx = 0;
  for (int i = 0; i < m; i++) {
    cin >> a[i];
    mx = max(mx, a[i]);
    a[i]--;
  }
  vector<int> b(s);
  for (int i = 0; i < s; i++) {
    cin >> b[i];
    mx = max(mx, b[i]);
    b[i]--;
  }
  vector<int> cnt(mx, 0);
  int zero = mx;
  for (int i = 0; i < s; i++) {
    cnt[b[i]]--;
    if (cnt[b[i]] == -1) {
      zero--;
    }
  }
  vector<int> ptr(m);
  ptr[0] = -1;
  while (ptr[0] + 1 < m && (ptr[0] + 1 < k || zero != mx)) {
    cnt[a[ptr[0] + 1]]++;
    if (cnt[a[ptr[0] + 1]] == 0) {
      zero++;
    }
    ptr[0]++;
  }
  if (ptr[0] + 1 < k || zero != mx) {
    ptr[0] = m;
  }
  for (int i = 1; i < m; i++) {
    cnt[a[i - 1]]--;
    if (cnt[a[i - 1]] == -1) {
      zero--;
    }
    ptr[i] = ptr[i - 1];
    if (ptr[i] == m) {
      continue;
    }
    while (ptr[i] + 1 < m && (ptr[i] - i + 1 < k || zero != mx)) {
      cnt[a[ptr[i] + 1]]++;
      if (cnt[a[ptr[i] + 1]] == 0) {
        zero++;
      }
      ptr[i]++;
    }
    if (ptr[i] - i + 1 < k || zero != mx) {
      ptr[i] = m;
    }
  }
  for (int i = 0; i < m; i++) {
    if (ptr[i] != m) {
      int need = ptr[i] - i + 1 - k + i % k;
      if (m - need < n * k) {
        continue;
      }
      vector<int> who;
      for (int j = 0; j < i % k; j++) {
        who.push_back(j);
      }
      for (int j = 0; j < mx; j++) {
        cnt[j] = 0;
      }
      for (int j = 0; j < s; j++) {
        cnt[b[j]]--;
      }
      set<int> B;
      for (int j = i; j <= ptr[i]; j++) {
        if (cnt[a[j]] < 0) {
          cnt[a[j]]++;
          B.insert(j);
        }
      }
      for (int j = i; j <= ptr[i]; j++) {
        if (B.find(j) == B.end() && (int)B.size() < k) {
          B.insert(j);
        }
      }
      for (int j = i; j <= ptr[i]; j++) {
        if (B.find(j) == B.end()) {
          who.push_back(j + 1);
        }
      }
      cout << who.size() << endl;
      for (int j = 0; j < (int)who.size(); j++) {
        cout << who[j] << " ";
      }
      return 0;
    }
  }
  cout << "-1\n";
  return 0;
}
