#include <bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define ii pair<int,int>
#define vii vector<ii>
#define ALL(x) begin(x), end(x)
void solve() {
int n, d, m;
cin >> n >> d >> m;
vii jobs(m);
for (int i = 0; i < m; ++i) {
cin >> jobs[i].first;
jobs[i].second = i + 1;
}
sort(ALL(jobs));
vector<vi> dist(n + 1);
auto feasible_and_fill = [&](int machines, bool fill) -> bool {
if (fill)
for (int i = 0; i <= n; ++i) dist[i].clear();
priority_queue<int, vi, greater<int>> pq;
for (int i = 0; i < machines; ++i) pq.push(1);
for (auto [a, id] : jobs) {
auto t = pq.top(); pq.pop();
if (t > a + d) return false;
int s = max(t, a);
if (fill){
// schedule on day s
dist[s].push_back(id);
}
// update machine: next free becomes s + 1
pq.push(s + 1);
}
return true;
};
int l = 1, r = m, ans = m;
while (l <= r) {
int mid = (l + r) / 2;
if (feasible_and_fill(mid, false)) {
ans = mid;
r = mid - 1;
} else {
l = mid + 1;
}
}
feasible_and_fill(ans, true);
cout << ans << '\n';
for (int day = 1; day <= n; ++day) {
for (int id : dist[day]) cout << id << ' ';
cout << "0\n";
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int tt = 1;
while (tt--) solve();
}
