#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int N, D, M;
pair<int, vector<vector<int>>> is_feasible(const vector<pair<int, int>>& jobs, int machine_count) {
vector<vector<int>> schedule(N);
int req_num = 0;
for (int day = 1; day <= N; ++day) {
for (int i = 0; i < machine_count; ++i) {
if (jobs[req_num].first > day) {
break;
}
if (jobs[req_num].first + D >= day) {
schedule[day - 1].push_back(jobs[req_num].second);
req_num++;
} else {
return {0, schedule};
}
if (req_num == M) {
return {1, schedule};
}
}
}
return {0, schedule};
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N >> D >> M;
vector<pair<int, int>> jobs(M);
for (int i = 0; i < M; ++i) {
cin >> jobs[i].first;
jobs[i].second = i + 1;
}
sort(jobs.begin(), jobs.end());
vector<vector<int>> result;
int l = 1, r = M;
while (l < r) {
int machine_num = (l + r) / 2;
auto cur_result = is_feasible(jobs, machine_num);
if (cur_result.first) {
r = machine_num;
result = cur_result.second;
} else {
l = machine_num + 1;
}
}
cout << l << "\n";
for (int i = 0; i < N; ++i) {
for (int idx : result[i]) {
cout << idx << " ";
}
cout << "0\n";
}
return 0;
}
