#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target( \
    "sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,mmx,avx,tune=native")
using namespace std;
const int MOD = 1000000007;
const int UNDEF = -1;
const int INF = 1 << 30;
template <typename T>
inline bool chkmax(T &aa, T bb) {
  return aa < bb ? aa = bb, true : false;
}
template <typename T>
inline bool chkmin(T &aa, T bb) {
  return aa > bb ? aa = bb, true : false;
}
int rint();
char rch();
long long rlong();
const int mn = (5e5) + 4;
int b[mn], c[mn], a[mn];
bool f[mn];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int m, k, _n, s;
  cin >> m >> k >> _n >> s;
  for (int i = 0; i < m; i++) cin >> a[i];
  int extra = m - k * _n;
  for (int i = 0; i < s; i++) {
    int x;
    cin >> x;
    ++b[x];
  }
  int req = 0;
  for (int x = 0; x < mn; x++)
    if (b[x] > 0) req++;
  int has = 0;
  int L = 0;
  for (int R = 0; R < m; R++) {
    {
      int x = a[R];
      if (b[x] > 0) {
        ++c[x];
        if (c[x] == b[x]) ++has;
      }
    }
    while (L < R) {
      int x = a[L];
      if (b[x] > 0) {
        if (c[x] <= b[x]) break;
        --c[x];
      }
      ++L;
    };
    int innerrm = R - L + 1 - k;
    int outerrm = L % k;
    if (has == req && innerrm + outerrm <= extra) {
      if (innerrm < 0) {
        outerrm += innerrm;
        innerrm = 0;
      }
      chkmax(outerrm, 0);
      memset(c, 0, sizeof c);
      for (int q = L; q <= R; q++) {
        int x = a[q];
        if (b[x] > 0) {
          ++c[x];
          if (c[x] <= b[x]) {
            f[q] = true;
          }
        }
      }
      vector<int> vans;
      for (int q = 0; q < outerrm; q++) {
        vans.push_back(q);
      }
      for (int q = L; q <= R; q++) {
        if (innerrm == 0) break;
        if (!f[q]) {
          vans.push_back(q);
          innerrm--;
        }
      }
      int sz = vans.size();
      printf("%d\n", ((int)vans.size()));
      for (auto &w : vans) printf("%d ", w + 1);
      printf("\n");
      exit(0);
    }
  }
  printf("-1\n");
}
static char stdinBuffer[1024];
static char *stdinDataEnd = stdinBuffer + sizeof(stdinBuffer);
static const char *stdinPos = stdinDataEnd;
void readAhead(size_t amount) {
  size_t remaining = stdinDataEnd - stdinPos;
  if (remaining < amount) {
    memmove(stdinBuffer, stdinPos, remaining);
    size_t sz = fread(stdinBuffer + remaining, 1,
                      sizeof(stdinBuffer) - remaining, stdin);
    stdinPos = stdinBuffer;
    stdinDataEnd = stdinBuffer + remaining + sz;
    if (stdinDataEnd != stdinBuffer + sizeof(stdinBuffer)) *stdinDataEnd = 0;
  }
}
int rint() {
  readAhead(16);
  int x = 0;
  bool neg = false;
  while (*stdinPos == ' ' || *stdinPos == '\n') ++stdinPos;
  if (*stdinPos == '-') {
    ++stdinPos;
    neg = true;
  }
  while (*stdinPos >= '0' && *stdinPos <= '9') {
    x *= 10;
    x += *stdinPos - '0';
    ++stdinPos;
  }
  return neg ? -x : x;
}
char rch() {
  readAhead(16);
  while (*stdinPos == ' ' || *stdinPos == '\n') ++stdinPos;
  char ans = *stdinPos;
  ++stdinPos;
  return ans;
}
long long rlong() {
  readAhead(32);
  long long x = 0;
  bool neg = false;
  while (*stdinPos == ' ' || *stdinPos == '\n') ++stdinPos;
  if (*stdinPos == '-') {
    ++stdinPos;
    neg = true;
  }
  while (*stdinPos >= '0' && *stdinPos <= '9') {
    x *= 10;
    x += *stdinPos - '0';
    ++stdinPos;
  }
  return neg ? -x : x;
}
