import java.io.*;
import java.util.*;
import java.util.function.Function;
public class jobs {
public static void main(String[] args) throws IOException {
FastInputReader reader = new FastInputReader(System.in);
int n = reader.nextInt(); // Number of days
int d = reader.nextInt(); // Delay allowed
int m = reader.nextInt(); // Number of events
if (m <= 300000) {
// Use the ArrayList-based implementation for smaller cases
handleSmallCases(reader, n, d, m);
} else {
// Use the C++ equivalent logic for larger cases
handleLargeCasesCppEquivalent(reader, n, d, m);
}
}
private static void handleSmallCases(FastInputReader reader, int n, int d, int m) throws IOException {
List<Pair> a = new ArrayList<>(m + 2);
for (int i = 1; i <= m; i++) {
a.add(new Pair(reader.nextInt(), i));
}
a.add(new Pair(1000000000, 0)); // Dummy pair for boundary
a.sort(Comparator.comparingInt(p -> p.fr));
int l = 0, r = m;
while (r - l > 1) {
int mid = (l + r) / 2;
int p = 0;
for (int i = 1; i <= n; i++) {
if (a.get(p).fr + d < i) {
break;
}
int cnt = 0;
while (cnt < mid && p < m && a.get(p).fr <= i) {
cnt++;
p++;
}
}
if (p >= m) {
r = mid;
} else {
l = mid;
}
}
System.out.println(r);
StringBuilder sb = new StringBuilder();
int p = 0;
for (int i = 1; i <= n; i++) {
int cnt = 0;
while (cnt < r && p < m && a.get(p).fr <= i) {
sb.append(a.get(p).sc).append(" ");
cnt++;
p++;
}
sb.append("0\n");
}
System.out.print(sb);
}
private static void handleLargeCasesCppEquivalent(FastInputReader reader, int n, int d, int m) throws IOException {
ArrayList<Integer>[] c = new ArrayList[n];
for (int i = 0; i < n; i++) {
c[i] = new ArrayList<>();
}
for (int i = 0; i < m; i++) {
int t = reader.nextInt() - 1;
c[t].add(i);
}
Pair[] in = new Pair[m];
List<Integer>[] ans = new ArrayList[n];
for (int i = 0; i < n; i++) {
ans[i] = new ArrayList<>();
}
// Check function translated from C++
Function<Integer, Boolean> check = x -> {
int cur = 0, len = 0;
for (int i = 0; i < n; i++) {
if (cur < len && in[cur].fr <= i) {
return false;
}
int end = i + d + 1;
for (int cVal : c[i]) {
in[len++] = new Pair(end, cVal);
}
int left = x;
while (left-- > 0 && cur < len) {
ans[i].add(in[cur++].sc);
}
}
return cur == len;
};
int lo = 1, hi = m;
while (lo < hi) {
int mid = (lo + hi) / 2;
if (check.apply(mid)) {
hi = mid;
} else {
lo = mid + 1;
}
}
check.apply(lo);
System.out.println(lo);
for (List<Integer> list : ans) {
for (int x : list) {
System.out.print((x + 1) + " ");
}
System.out.println(0);
}
}
static class Pair implements Comparable<Pair> {
int fr, sc;
Pair(int fr, int sc) {
this.fr = fr;
this.sc = sc;
}
@Override
public int compareTo(Pair other) {
return Integer.compare(this.fr, other.fr);
}
}
static class FastInputReader {
private final DataInputStream din;
private final byte[] buffer;
private int bufferPointer, bytesRead;
public FastInputReader(InputStream in) {
din = new DataInputStream(in);
buffer = new byte[1 << 16]; // 64 KB buffer
bufferPointer = bytesRead = 0;
}
public int nextInt() throws IOException {
int ret = 0;
byte c = 0;
while (bufferPointer < bytesRead || refillBuffer()) {
c = buffer[bufferPointer++];
if (c > ' ') break; // Skip non-digit
}
boolean neg = (c == '-');
if (neg) c = buffer[bufferPointer++];
while (c >= '0' && c <= '9') {
ret = ret * 10 + (c - '0');
if (bufferPointer == bytesRead && !refillBuffer()) break;
c = buffer[bufferPointer++];
}
return neg ? -ret : ret;
}
private boolean refillBuffer() throws IOException {
bytesRead = din.read(buffer, 0, buffer.length);
bufferPointer = 0;
return bytesRead > 0;
}
}
}
