#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
int n, m, k, a;
vector<pair<int, int>> all;
vector<int> v;
int main() {
  scanf("%d%d%d", &n, &m, &k);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a);
    all.push_back(make_pair(a, -1));
  }
  for (int i = 0; i < m; i++) {
    scanf("%d", &a);
    all.push_back(make_pair(a, i));
  }
  sort(all.begin(), all.end());
  int day = 0, c = 0, ans = 0;
  for (int i = 0; i < all.size(); i++) {
    if (all[i].second == -1)
      if (all[i].first >= day) {
        c++;
        if (c == k) {
          day++;
          c = 0;
        }
      } else {
        printf("-1\n");
        return 0;
      }
    else if (all[i].first >= day) {
      c++;
      ans++;
      v.push_back(all[i].second);
      if (c == k) {
        day++;
        c = 0;
      }
    }
  }
  printf("%d ", ans);
  for (int i = 0; i < v.size(); i++) printf("%d ", v[i] + 1);
  v.clear();
  all.clear();
  return 0;
}
