import java.io.*;
import java.util.*;
public class jobs {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine());
int n = Integer.parseInt(st.nextToken());
int d = Integer.parseInt(st.nextToken());
int m = Integer.parseInt(st.nextToken());
int mxn = 1000005;
Pair[] a = new Pair[m + 2];
st = new StringTokenizer(br.readLine());
for (int i = 1; i <= m; i++) {
a[i] = new Pair(Integer.parseInt(st.nextToken()), i);
}
a[m + 1] = new Pair(1000000000, 0); // Dummy pair
Arrays.sort(a, 1, m + 1);
int l = 0, r = m;
while (r - l > 1) {
int mid = (l + r) / 2;
int p = 1;
for (int i = 1; i <= n; i++) {
if (a[p].fr + d < i) {
break;
}
int cnt = 0;
while (cnt < mid && p <= m && a[p].fr <= i) {
cnt++;
p++;
}
}
if (p > m) {
r = mid;
} else {
l = mid;
}
}
System.out.println(r);
int p = 1;
StringBuilder sb = new StringBuilder();
for (int i = 1; i <= n; i++) {
int cnt = 0;
while (cnt < r && p <= m && a[p].fr <= i) {
sb.append(a[p].sc).append(" ");
cnt++;
p++;
}
sb.append("0\n");
}
System.out.print(sb);
}
static class Pair implements Comparable<Pair> {
int fr, sc;
Pair(int fr, int sc) {
this.fr = fr;
this.sc = sc;
}
public int compareTo(Pair other) {
return Integer.compare(this.fr, other.fr);
}
}
}
