#include <fstream>
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <cstring>
#include <climits>
using namespace std;
using ll = long long;
const int INF = 2e5 + 5;
int n, d, m;
vector<pair<int, int>> a;
bool ok (int machines) {
int current_day = 1;
int num_machines = 0;
int current_job = 0;
while (current_job < m) {
if (a[current_job].first > current_day) {
current_day++;
num_machines = 0;
continue;
}
if (current_day - a[current_job].first > d) {
return false;
}
num_machines++;
if (num_machines == machines) {
current_day++;
num_machines = 0;
}
current_job++;
}
return true;
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(0);
//ifstream fin(".in");
//ofstream fout(".out");
cin >> n >> d >> m;
a.resize(m);
for (int i = 0; i < m; i++){
cin >> a[i].first;
a[i].second = i + 1;
}
sort(a.begin(), a.end());
int left = 0, right = 1000000;
while (right > left + 1){
int mid = (left + right) / 2;
if (ok(mid)){
right = mid;
} else{
left = mid;
}
}
cout << right << "\n";
int count = n;
for (int i = 0; i < m; i += right){
for (int j = i; j < min(m, i + right); j++){
cout << a[j].second << " ";
}
count--;
cout << 0 << "\n";
}
for (int i = 0; i < count; i++){
cout << 0 << "\n";
}
return 0;
}
/*
* 8 2 12
1 2 4 2 1 3 5 6 1 3 6 4
*/
//
