#include <bits/stdc++.h>
using namespace std;
int arr[500010];
int cntB[500010];
int cnt[500010];
int main(void) {
  int N, M, K, S;
  scanf("%d %d %d %d", &M, &K, &N, &S);
  for (int i = 0; i < M; i++) scanf("%d", &arr[i]);
  int ones = 0;
  for (int i = 0; i < S; i++) {
    int a;
    scanf("%d", &a);
    if (!cnt[a]) ones++;
    cnt[a]++;
    cntB[a]++;
  }
  int j = 0;
  for (int i = 0; i < M; i++) {
    while (j < M && i / K + (M - 1 - j) / K >= N - 1) {
      cnt[arr[j]]--;
      if (cnt[arr[j]] == 0) ones--;
      if (!ones && j - i + 1 >= K) {
        vector<int> result;
        for (int x = 0; x < i % K; x++) result.push_back(x);
        for (int x = i; x <= j; x++) {
          if (cntB[arr[x]])
            cntB[arr[x]]--;
          else if (result.size() < i % K + j - i + 1 - K)
            result.push_back(x);
        }
        printf("%d\n", result.size());
        for (int r : result) printf("%d ", r + 1);
        printf("\n");
        return 0;
      }
      j++;
    }
    if (cnt[arr[i]] == 0) ones++;
    cnt[arr[i]]++;
  }
  printf("-1\n");
  return 0;
}
