//#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <string>
#include <tuple>
#include <numeric>
#include <climits>
#include <bitset>
#include <iomanip>
using namespace std;
//change the long long to int if you need to save memory/time really badly
typedef long long ll;
//Comment this define when working on interactive problems
#define endl "\n"
#define sqrt(n) sqrt((long double) n)
const ll MAXN = 5e5 + 5;
const ll ZER = 0;
const ll ONE = 1;
const ll INF = LLONG_MAX;
const ll MOD = 998244353;
void solve(ll ca) {
ll n, d, m;
cin >> n >> d >> m;
pair<ll, ll> requests[m];
for (ll i = 0; i < m; i++) {
cin >> requests[i].first;
requests[i].second = i;
}
sort(requests, requests+m);
ll lo = 1; ll hi = 1e8;
hi++;
while (lo < hi) {
ll mid = lo + (hi - lo) / 2;
bool works = true;
ll day = 1; ll cnt = mid;
for (ll i = 0; i < m; i++) {
if (day < requests[i].first) {
day = requests[i].first;
cnt = mid;
}
if (abs(day - requests[i].first) > d) {
works = false;
break;
}
cnt--;
if (cnt == 0) {
day++;
cnt = mid;
}
}
if (works) {
hi = mid;
} else {
lo = mid+1;
}
}
cout << lo << endl;
vector<ll> ans[n];
ll day = 1; ll cnt = lo;
for (ll i = 0; i < m; i++) {
if (day < requests[i].first) {
day = requests[i].first;
cnt = lo;
}
cnt--;
ans[day-1].push_back(requests[i].second+1);
//cout << requests[i].second + 1 << "LOL" << endl;
if (cnt == 0) {
day++;
cnt = lo;
}
}
for (ll i = 0; i < n; i++) {
for (auto el: ans[i]) {
cout << el << " ";
}
cout << 0 << endl;
}
return;
}
int main()
{
//Fast IO
ios::sync_with_stdio(false);
cin.tie(nullptr);
ll t = 1;
//cin >> t;
ll co = 1;
while (t--) {
solve(co);
++co;
}
}
