#include <bits/stdc++.h>
using namespace std;
template <class T>
void _R(T &x) {
  cin >> x;
}
void _R(int &x) { scanf("%d", &x); }
void _R(long long &x) { scanf("%lld", &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template <class T, class... U>
void R(T &head, U &...tail) {
  _R(head);
  R(tail...);
}
template <class T>
void _W(const T &x) {
  cout << x;
}
void _W(const int &x) { printf("%d", x); }
void _W(const long long &x) { printf("%lld", x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template <class T, class U>
void _W(const pair<T, U> &x) {
  _W(x.first);
  putchar(' ');
  _W(x.second);
}
template <class T>
void _W(const vector<T> &x) {
  for (auto i = x.begin(); i != x.end(); _W(*i++))
    if (i != x.cbegin()) putchar(' ');
}
void W() {}
template <class T, class... U>
void W(const T &head, const U &...tail) {
  _W(head);
  putchar(sizeof...(tail) ? ' ' : '\n');
  W(tail...);
}
int MOD = 1e9 + 7;
void ADD(long long &x, long long v) {
  x = (x + v) % MOD;
  if (x < 0) x += MOD;
}
const int SIZE = 1e6 + 10;
int a[SIZE];
int cnt[SIZE], gg[SIZE];
int m, k, n, s;
bool choose[SIZE];
void print(int ll, int rr) {
  int need = n - 1;
  int v = min((ll - 1) / k, need);
  for (int i = (1); i <= (v * k); ++i) choose[i] = 1;
  need -= v;
  v = min((m - rr + 1) / k, need);
  for (int i = (1); i <= (v * k); ++i) choose[m + 1 - i] = 1;
  need = k;
  memset((cnt), 0, sizeof((cnt)));
  for (int i = (ll); i < (rr); ++i) {
    if (cnt[a[i]] < gg[a[i]]) {
      cnt[a[i]]++;
      choose[i] = 1;
      need--;
    }
  }
  for (int i = (1); i <= (m); ++i) {
    if (need > 0 && !choose[i]) {
      need--;
      choose[i] = 1;
    }
  }
  vector<int> AA;
  for (int i = (1); i <= (m); ++i) {
    if (!choose[i]) AA.push_back(i);
  }
  W(((int)(AA).size()));
  W(AA);
}
int main() {
  R(m, k, n, s);
  for (int i = (1); i <= (m); ++i) R(a[i]);
  for (int i = (1); i <= (s); ++i) {
    int x;
    R(x);
    gg[x]++;
  }
  int rr = 1;
  int need = s;
  for (int i = (1); i <= (m); ++i) {
    while (need > 0 && rr <= m) {
      if (cnt[a[rr]] < gg[a[rr]]) {
        need--;
      }
      cnt[a[rr]]++;
      rr++;
    }
    if (!need) {
      if ((i - 1) / k + (m - rr + 1) / k >= n - 1) {
        print(i, rr);
        return 0;
      }
    }
    if (cnt[a[i]] <= gg[a[i]]) {
      need++;
    }
    cnt[a[i]]--;
  }
  W(-1);
  return 0;
}
