#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, m, k, n, s;
  cin >> m >> k >> n >> s;
  int a[m + 1], b[s + 1];
  for (i = 1; i <= m; i++) {
    cin >> a[i];
  }
  for (i = 1; i <= s; i++) {
    cin >> b[i];
  }
  map<int, int> pattern;
  map<int, int>::iterator pit;
  for (i = 1; i <= s; i++) {
    pattern[b[i]]++;
  }
  map<int, pair<int, int> > map1;
  map<int, pair<int, int> >::iterator it;
  pair<int, int> p1;
  int d = m - n * k;
  for (i = 1; i <= d + k; i++) {
    p1.first = i;
    p1.second = map1[a[i]].second + 1;
    map1[a[i]] = p1;
  }
  for (i = 1; i <= n; i++) {
    for (pit = pattern.begin(); pit != pattern.end(); pit++) {
      if (pit->second > map1[pit->first].second) {
        break;
      }
    }
    if (pit == pattern.end()) {
      cout << d << endl;
      int diff = d;
      for (j = (i - 1) * k + 1; j <= (i)*k + d; j++) {
        if (!diff) {
          return 0;
        }
        if (pattern[a[j]]) {
          pattern[a[j]]--;
        } else {
          diff--;
          cout << j << " ";
        }
      }
      return 0;
    }
    for (j = 1; j <= k; j++) {
      map1[a[(i - 1) * k + j]].second--;
      if (!map1[a[(i - 1) * k + j]].second) {
        map1.erase(a[(i - 1) * k + j]);
      }
    }
    for (j = 1; j <= k; j++) {
      p1.first = d + i * k + j;
      p1.second = map1[a[d + i * k + j]].second + 1;
      map1[a[d + i * k + j]] = p1;
    }
  }
  if (i == n + 1) {
    cout << -1;
  }
}
