#include <bits/stdc++.h>
using namespace std;
long long bin_pow(long long a, long long b) {
  if (b == 0) return 1;
  if (b % 2 == 0) {
    long long t = bin_pow(a, b / 2);
    return t * t % 1000000007;
  } else
    return a * bin_pow(a, b - 1) % 1000000007;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long t = 1, n, m, k = 0, sum = 0, l = 0, r = 0, x = 0, y = 0, z = 0,
            ans = 0, mn = LLONG_MAX, mx = LLONG_MIN;
  cin >> m >> k >> n >> x;
  set<long long> s;
  vector<long long> a(m), b(x), c(500001), d(500001);
  for (int i = 0; i < m; i++) cin >> a[i];
  for (int i = 0; i < x; i++) cin >> b[i], c[b[i]]++, s.insert(b[i]);
  y = m - n * k;
  vector<long long> dp(m);
  for (int i = 0; i < m; i++) {
    while (r < m && s.size()) {
      d[a[r]]++;
      if (d[a[r]] == c[a[r]]) s.erase(s.lower_bound(a[r]));
      r++;
    }
    if (s.size())
      dp[i] = LLONG_MAX / 8;
    else
      dp[i] = r - 1;
    d[a[i]]--;
    if (d[a[i]] == c[a[i]] - 1) s.insert(a[i]);
  }
  for (int i = 0; i < m; i++) {
    z = i / k;
    z *= k;
    z = i - z;
    if (dp[i] - i + 1 - k + z <= y) {
      cout << z + max(0ll, dp[i] - i + 1 - k) << "\n";
      for (int j = 0; j < z; j++) cout << j + 1 << " ";
      long long cnt = 0;
      for (int j = i; j <= dp[i]; j++) {
        if (c[a[j]]) {
          c[a[j]]--;
        } else {
          if (cnt == max(dp[i] - i + 1 - k, 0ll)) break;
          cout << j + 1 << " ";
          cnt++;
        }
      }
      return 0;
    }
  }
  cout << -1;
  return 0;
}
