#include <bits/stdc++.h>
using namespace std;
int a[500005];
int b[500005];
int c[500005];
set<int> q[500005];
void find() {
  for (int i = 0; i < 5e5 + 5; i++) c[i] = 0, q[i].clear();
  int m, k, n, s1;
  cin >> m >> k >> n >> s1;
  int i, j;
  for (i = 0; i < m; i++) cin >> a[i];
  for (i = 0; i < s1; i++) cin >> b[i], c[b[i]]++;
  j = 0;
  for (int i = 0; i < 5e5 + 5; i++)
    if (c[i] > 0) j++;
  set<int> s;
  s.clear();
  for (i = 0; i < m; i++) {
    q[a[i]].insert(i);
    if (q[a[i]].size() >= c[a[i]] && c[a[i]] > 0) {
      int x = *q[a[i]].begin();
      if (q[a[i]].size() == c[a[i]])
        s.insert(x);
      else {
        q[a[i]].erase(x);
        s.erase(x);
        s.insert(*q[a[i]].begin());
      }
    }
    if (s.size() == j) {
      int l = *s.begin(), r = i;
      if (((m - r - 1) / k) + (l / k) < n - 1) continue;
      if (r - l + 1 <= k) {
        int y = 0;
        if ((l / k) != (r / k)) y = max(0, l - (l / k * k) - (k - (r - l + 1)));
        if (y >= 0) {
          cout << y << "\n";
          for (int j = l / k * k; j < l && y > 0; j++, y--) {
            cout << j + 1 << " ";
          }
          cout << "\n";
          return;
        }
      } else {
        vector<int> e;
        e.clear();
        for (int j = l / k * k; j < l; j++) e.push_back(j);
        multiset<int> g;
        for (int j = l; j <= r; j++) {
          g.insert(a[j]);
        }
        for (int j = 0; j < s1; j++) g.erase(g.find(b[j]));
        int t = r - l + 1 - s1;
        k -= s1;
        for (int j = l; j <= r; j++) {
          if (g.find(a[j]) != g.end() && t > k) {
            g.erase(g.find(a[j]));
            e.push_back(j);
            t--;
          }
        }
        sort(e.begin(), e.end());
        cout << e.size() << "\n";
        for (int j = 0; j < e.size(); j++) cout << e[j] + 1 << " ";
        cout << "\n";
        return;
      }
    }
  }
  cout << -1;
  cout << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int t;
  t = 1;
  while (t--) {
    find();
  }
  return 0;
}
