#include <bits/stdc++.h>
using namespace std;
const long long MAXN = 500100;
void fastIO() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int n, k, m, s, l, r, now, op[MAXN], a[MAXN], q;
int main() {
  fastIO();
  cin >> m >> k >> n >> s;
  l = -1;
  r = 0;
  for (int i = 0; i < m; i++) cin >> a[i];
  for (int i = 0; i < s; i++) {
    cin >> q;
    op[q]++;
  }
  for (int i = 0; i < MAXN - 1; i++) {
    if (op[i] > 0) now++;
  }
  for (r = 0; r < m; r++) {
    op[a[r]]--;
    if (op[a[r]] == 0) now--;
    while (now == 0) {
      if (((l + 1) % k) + max(r - l - k, 0) - max(k + l - r, 0) <= m - k * n) {
        if (r - l - k <= 0) {
          q = max(((l + 1) % k) + max(r - l - k, 0) - max(k + l - r, 0), 0);
          cout << q << "\n";
          for (int i = 1; i <= q; i++) cout << i << " ";
          return 0;
        } else {
          q = r - l - k;
          cout << ((l + 1) % k) + r - l - k << "\n";
          for (int i = 1; i <= (l + 1) % k; i++) cout << i << " ";
          for (int i = l + 1; q > 0; i++) {
            if (op[a[i]] != 0) {
              cout << i + 1 << " ";
              op[a[i]]++;
              q--;
            }
          }
          return 0;
        }
      }
      l++;
      op[a[l]]++;
      if (op[a[l]] == 1) {
        now++;
        break;
      }
    }
  }
  cout << -1;
  return 0;
}
