#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 10;
int m, k, n, s, cnt;
int a[N], b[N], c[N], d[N];
int main() {
  scanf("%d%d%d%d", &m, &k, &n, &s);
  for (int i = 1; i <= m; i++) scanf("%d", &a[i]);
  for (int i = 1, x; i <= s; i++) {
    scanf("%d", &x);
    if (!b[x]) cnt++;
    b[x]++;
  }
  for (int l = 1, r = 1; r <= m; r++) {
    ++c[a[r]];
    cnt -= c[a[r]] == b[a[r]];
    while (!cnt && l <= m && r - l + 1 > k && c[a[l]] > b[a[l]]) c[a[l]]--, l++;
    if (!cnt && r - l + 1 >= k) {
      int qaq = (l - 1) % k + (r - l + 1 - k);
      if (qaq > m - n * k) continue;
      cout << qaq << endl;
      for (int i = 1; i <= (l - 1) % k && qaq; i++) printf("%d ", i), qaq--;
      for (int i = l; i <= r && qaq; i++) {
        if (d[a[i]] + 1 > b[a[i]]) printf("%d ", i), qaq--;
        d[a[i]]++;
      }
      return 0;
    }
  }
  puts("-1");
  return 0;
}
