#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 7;
int a[maxn];
int required[maxn];
int now[maxn];
bool cut[maxn];
int m, k, n, s;
int sum;
int tot;
int solve() {
  int rest = m - n * k;
  for (int i = 1; i <= min(m, 1 + k + rest - 1); i++) {
    if (!required[a[i]]) continue;
    now[a[i]]--;
    if (now[a[i]] >= 0) sum--;
  }
  if (sum == 0) return 1;
  for (int i = 1 + k; i + k - 1 <= m; i += k) {
    for (int j = i - k; j < i; j++) {
      if (required[a[j]]) {
        now[a[j]]++;
        if (now[a[j]] > 0) sum++;
      }
    }
    for (int j = i + rest; j <= min(m, i + k + rest - 1); j++) {
      if (j > m) break;
      if (!required[a[j]]) continue;
      now[a[j]]--;
      if (now[a[j]] >= 0) sum--;
    }
    if (sum == 0) return i;
  }
  return -1;
}
vector<int> ans;
void print(int start) {
  ans.clear();
  int rest = m - n * k;
  for (int i = start; rest; i++) {
    if (rest == 0) break;
    if (!required[a[i]]) {
      ans.push_back(i);
      rest--;
      continue;
    }
    required[a[i]]--;
    tot--;
  }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); i++) {
    if (i) cout << " ";
    cout << ans[i];
  }
  cout << endl;
}
int main() {
  while (cin >> m >> k >> n >> s) {
    for (int i = 1; i <= m; i++) {
      cin >> a[i];
      required[i] = 0;
      cut[i] = 0;
    }
    sum = 0;
    for (int i = 1; i <= s; i++) {
      int temp;
      cin >> temp;
      required[temp]++;
      sum++;
      now[temp]++;
    }
    tot = sum;
    int l = solve();
    if (l == -1)
      cout << -1 << endl;
    else {
      print(l);
    }
  }
}
