#include <bits/stdc++.h>
using namespace std;
const long long int N = 5e5 + 5;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int m, k, n, s;
  cin >> m >> k >> n >> s;
  long long int ary[m];
  for (long long int i = 0; i < m; ++i) {
    cin >> ary[i];
  }
  long long int t = k + m - n * k;
  long long int f[N];
  long long int mk[N];
  memset(mk, 0, sizeof(mk));
  long long int c = 0;
  for (long long int i = 0; i < s; ++i) {
    long long int a;
    cin >> a;
    f[a]++;
    if (mk[a] == 0) c++;
    mk[a]++;
  }
  long long int st = -1, ed = -1;
  long long int p = 0;
  long long int pre = -1;
  while (p + k <= m) {
    for (long long int i = max(p, pre + 1); i < min(p + t, m); ++i) {
      f[ary[i]]--;
      if (mk[ary[i]] > 0 && f[ary[i]] == 0) {
        c--;
      }
    }
    if (c == 0) {
      st = p;
      ed = min(p + t, m) - 1;
    }
    for (long long int i = p; i < p + k; ++i) {
      f[ary[i]]++;
      if (mk[ary[i]] > 0 && f[ary[i]] == 1) {
        c++;
      }
    }
    pre = p + t - 1;
    p += k;
  }
  if (st == -1) {
    cout << -1 << "\n";
  } else {
    cout << ed - st + 1 - k << "\n";
    long long int cnt = ed - st + 1 - k;
    for (long long int i = 0; i < N; ++i) {
      f[i] = mk[i];
    }
    for (long long int i = st; i < ed + 1; ++i) {
      if (cnt <= 0) break;
      if (mk[ary[i]] > 0 && f[ary[i]] > 0) {
        f[ary[i]]--;
      } else {
        cnt--;
        cout << i + 1 << " ";
      }
    }
    cout << "\n";
  }
  return 0;
}
