import java.io.*;
import java.util.*;
public class jobs {
static int N, D, M;
static Pair[] requests;
public static void main(String[] args) throws IOException, FileNotFoundException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
N = Integer.parseInt(reader.readLine());
D = Integer.parseInt(reader.readLine());
M = Integer.parseInt(reader.readLine());
requests = new Pair[M];
String[] valString = reader.readLine().split(" ");
for(int i = 0; i < M; i++){
requests[i] = new Pair(Integer.parseInt(valString[i]), i + 1);
}
if(M >= 0){
return;
}
Arrays.sort(requests);
int a = 1;
int b = 1000000;
while(a != b){
int mid = (a + b)/2;
if(works(mid)){
b = mid;
} else {
a = mid + 1;
}
}
String[] returns = new String[N];
int machineIdx = 0;
int[] lastTask = new int[a];
for(int i = 0; i < M; i++){
lastTask[machineIdx] = Math.max(lastTask[machineIdx] + 1, requests[i].a);
int idx = lastTask[machineIdx] - 1;
if(returns[idx] == null){
returns[idx] = String.valueOf(requests[i].b);
} else {
returns[idx] += " " + requests[i].b;
}
machineIdx++;
machineIdx %= a;
}
System.out.println(a);
for(int i = 0; i < N; i++){
if(returns[i] != null){
System.out.println(returns[i] + " 0");
} else {
System.out.println("0");
}
}
}
public static boolean works(int machines){
int[] lastTask = new int[machines];
int machineIdx = 0;
for(int i = 0; i < M; i++){
lastTask[machineIdx] = Math.max(lastTask[machineIdx] + 1, requests[i].a);
if(lastTask[machineIdx] - requests[i].a > D){
return false;
}
machineIdx++;
machineIdx %= machines;
}
return true;
}
static class Pair implements Comparable<Pair>{
int a, b;
public Pair(int a, int b){
this.a = a;
this.b = b;
}
public int compareTo(Pair p){
return a - p.a;
}
}
}
