#include <bits/stdc++.h>
using namespace std;
struct Job {
int pos;
int index;
Job(int p, int i) : pos(p), index(i) {}
bool operator<(const Job &other) const {
return pos < other.pos;
}
};
bool work(int num, int d, vector<Job> &array) {
int m = array.size();
int batches = (m + num - 1) / num;
for (int i = 0; i < batches; i++) {
int start = i * num;
int end = min(start + num, m);
for (int j = start; j < end; j++) {
if (array[j].pos + d < i)
return false;
}
}
return true;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, d, m;
cin >> n >> d >> m;
vector<Job> array;
for (int i = 0; i < m; i++) {
int p;
cin >> p;
array.emplace_back(p - 1, i + 1);
}
sort(array.begin(), array.end());
int l = 1, r = m;
while (l <= r) {
int mid = (l + r) / 2;
if (work(mid, d, array))
r = mid - 1;
else
l = mid + 1;
}
cout << l << "\n";
int batches = (m + l - 1) / l;
int day = 0;
for (int i = 0; i < batches; i++) {
int start = i * l;
int end = min(start + l, m);
for (int j = start; j < end; j++)
cout << array[j].index << " ";
cout << "0\n";
day++;
}
while (day < n) {
cout << "0\n";
day++;
}
}
