#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 0;
  char ch = getchar();
  for (; ch < '0' || ch > '9'; ch = getchar())
    if (ch == '-') f = 1;
  for (; ch >= '0' && ch <= '9'; ch = getchar())
    x = (x << 3) + (x << 1) + (ch ^ 48);
  return f ? -x : x;
}
int s[10000000 + 10], b[1000010], p[1000010], ans[1000010], sum;
int n, m, t;
inline bool cmp(int x, int y) { return b[x] < b[y]; }
int main() {
  n = read();
  m = read();
  t = read();
  for (int i = 1; i <= n; i++) s[read()]++;
  for (int i = 10000000; i; i--)
    if (s[i] >= t) s[i - 1] += s[i] - t, s[i] = t;
  if (s[0] > t) return printf("-1") & 0;
  for (int i = 1; i <= m; i++) b[i] = read(), p[i] = i;
  sort(p + 1, p + m + 1, cmp);
  for (int j = 0, i = 1, k; i <= m; i++) {
    k = p[i];
    for (; s[j] == t; j++)
      ;
    if (b[k] >= j) s[j]++, ans[sum++] = k;
  }
  printf("%d\n", sum);
  for (int i = 0; i < sum; i++) printf("%d ", ans[i]);
  return 0;
}
