#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 7;
int m, k, n, s, a[maxn], b[maxn], cnt[maxn], vis[maxn], pos, dff, lim, r, del,
    rm;
void solve() {
  cin >> m >> k >> n >> s;
  for (int i = 0; i < m; ++i) {
    cin >> a[i];
  }
  for (int i = 0; i < s; ++i) {
    cin >> b[i];
    vis[b[i]]++, dff += (vis[b[i]] == 1);
  }
  lim = m - n * k, r = -1;
  for (int l = 0; l < m; ++l) {
    while (r < m - 1 && pos < dff) {
      cnt[a[++r]]++;
      if (vis[a[r]] && cnt[a[r]] == vis[a[r]]) {
        pos++;
      }
    }
    if (pos == dff) {
      if (vis[a[l]] && cnt[a[l]] == vis[a[l]]) {
        pos--;
      }
      cnt[a[l]]--;
      if (l / k < n) {
        if (r / k == l / k) {
          cout << 0 << endl;
          return;
        }
        del = r - (l / k + 1) * k + 1;
        if (del > lim) {
          continue;
        }
        if (del <= r - l + 1 - s) {
          cout << del << endl;
          for (int i = l; del && i < r; ++i) {
            if (vis[a[i]]) {
              vis[a[i]]--;
            } else {
              cout << i + 1 << ' ';
              del--;
            }
          }
          cout << endl;
          return;
        }
        del = r - l - s + 1, rm = l + s - (l / k + 1) * k;
        if (del + rm > lim) {
          continue;
        }
        cout << del + rm << endl;
        for (int i = l - rm; i < l; ++i) {
          cout << i + 1 << ' ';
        }
        for (int i = l; i < r; ++i) {
          if (vis[a[i]]) {
            vis[a[i]]--;
          } else {
            cout << i + 1 << ' ';
          }
        }
        cout << endl;
        return;
      }
      del = r - n * k + 1;
      if (del > lim) {
        continue;
      }
      cout << del << endl;
      for (int i = n * k - s; i < n * k; ++i) {
        cout << i + 1 << ' ';
      }
      for (int i = n * k; i < r; ++i) {
        if (vis[a[i]]) {
          vis[a[i]]--;
        } else {
          cout << i + 1 << ' ';
        }
      }
      cout << endl;
      return;
    }
    break;
  }
  cout << -1 << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
