#include <bits/stdc++.h>
using namespace std;
struct day {
vector<int> reqs;
int due = 0;
};
vector<day> days;
int N;
bool check(int num) {
int jobs = 0, done = 0;
for (int i = 1; i <= N; i++) {
jobs = max(0, jobs + static_cast<int>(days[i].reqs.size()) - num);
done += num - days[i].due;
if (done < 0)
return false;
}
return true;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int D, M;
cin >> N >> D >> M;
days.resize(N+1);
for (int i = 1; i <= M; i++) {
int req;
cin >> req;
days[req].reqs.push_back(i);
days[req + D].due++;
}
int l = 1, r = 1e+6;
while (l < r) {
int mid = l + (r - l) / 2;
if (check(mid))
r = mid;
else
l = mid + 1;
}
cout << l << '\n';
queue<int> jobs;
for (int i = 1; i <= N; i++) {
for (const auto& i : days[i].reqs)
jobs.push(i);
for (int i = 0; i < l && !jobs.empty(); i++) {
cout << jobs.front() << ' ';
jobs.pop();
}
cout << "0\n";
}
}
