#include <bits/stdc++.h>
using namespace std;
int N, M, a, b, c, t, ans, K, S, mc, q[500007], n[500007], nl[500007];
int main() {
  scanf("%d%d%d%d", &M, &K, &N, &S);
  for (int i = 1; i <= M; i++) scanf("%d", &q[i]);
  int less = 0;
  for (int i = 1; i <= S; i++) {
    scanf("%d", &a);
    mc = max(mc, a);
    if (!nl[a]) less++;
    nl[a]++;
  }
  int p = 0;
  for (int i = 1; i <= M - K + 1; i++) {
    if (K == 1 || i % K == 1) {
      while (p <= M && (less || p < i)) {
        p++;
        n[q[p]]++;
        if (n[q[p]] == nl[q[p]]) less--;
      }
      if (p > M) break;
      if (p - i + 1 - K <= M - N * K) {
        ans = max(p - i + 1 - K, 0);
        printf("%d\n", ans);
        for (int j = 1; j <= mc; j++) n[j] = 0;
        int rm = 0;
        for (int j = i; j <= p; j++) {
          n[q[j]]++;
          if (n[q[j]] > nl[q[j]] && rm < ans) {
            printf("%d ", j);
            rm++;
          }
        }
        printf("\n");
        return 0;
      }
    }
    n[q[i]]--;
    if (n[q[i]] < nl[q[i]]) less++;
  }
  printf("-1\n");
  return 0;
}
