#include <bits/stdc++.h>
using namespace std;
int st[500010], sta[500010];
int a[500010], b[500010];
int main() {
  int m, K, n, s, now = 0, stp = 0, i, j;
  scanf("%d%d%d%d", &m, &K, &n, &s);
  for (i = 1; i <= m; i++) scanf("%d", &a[i]);
  for (i = 1; i <= s; i++) scanf("%d", &b[i]);
  for (i = 1; i <= s; i++) {
    if (!st[b[i]]) stp++;
    st[b[i]]++;
  }
  int R = 1;
  for (i = 1; i <= m; i++) {
    while (now < stp && R <= m) {
      if (sta[a[R]] == st[a[R]] - 1) now++;
      sta[a[R]]++;
      R++;
    }
    if (now == stp && (R - i - K) <= m - K * n && (i - 1) % K == 0) {
      if (R - i <= K) {
        printf("0\n");
        return 0;
      }
      printf("%d\n", (R - i) - K);
      now = (R - i) - K;
      for (j = i; j < R; j++) {
        if (sta[a[j]] > st[a[j]] && now) {
          printf("%d ", j);
          sta[a[j]]--;
          now--;
        }
      }
      printf("\n");
      return 0;
    }
    if (sta[a[i]] == st[a[i]]) now--;
    sta[a[i]]--;
  }
  printf("-1\n");
  return 0;
}
