#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 10;
int m, k, n, s, tot, del, a[N], b[N], c[N], d[N];
int main() {
  scanf("%d%d%d%d", &m, &k, &n, &s);
  del = m - k * n;
  for (int i = 1; i <= m; i++) scanf("%d", &a[i]);
  for (int i = 1, x; i <= s; i++) {
    scanf("%d", &x);
    b[x]++;
    if (b[x] == 1) tot++;
  }
  for (int l = 1, r = 1; r <= m; r++) {
    ++c[a[r]];
    tot -= c[a[r]] == b[a[r]];
    while (!tot && r - l + 1 > k && l <= m && c[a[l]] > b[a[l]]) --c[a[l]], l++;
    if (!tot && r - l + 1 >= k) {
      int del2 = (l - 1) % k + r - l + 1 - k;
      if (del2 > del) continue;
      printf("%d\n", del2);
      if (!del2) return 0;
      for (int i = 1; i <= (l - 1) % k && del2; i++) printf("%d ", i), del2--;
      for (int i = l; i <= r && del2; i++)
        if (d[a[i]] + 1 > b[a[i]])
          printf("%d ", i), del2--;
        else
          d[a[i]]++;
      return 0;
    }
  }
  printf("-1");
}
