#include <bits/stdc++.h>
using namespace std;
const int mxN = 1e5+1;
int n, D, m;
vector<int> days[mxN];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> D >> m;
for (int i=1, a; i<=m; ++i) {
cin >> a;
days[a].push_back(i);
}
int lo = 1, hi = 1e6;
while (lo < hi) {
int mid = (lo+hi)/2;
bool works = true;
// cnt, deadline
queue<pair<int, int>> q;
for (int i=1; i<=n && works; ++i) {
int left = mid;
if (days[i].size())
q.push({(int)days[i].size(), i+D});
while (!q.empty() && left) {
if (i > q.front().second) {
works = false;
break;
}
int sub = min(left, q.front().first);
left -= sub;
q.front().first -= sub;
if (!q.front().first)
q.pop();
}
}
if (works && q.empty())
hi = mid;
else
lo = mid+1;
}
cout << lo << '\n';
queue<int> q;
for (int i=1; i<=n; ++i) {
for (const int &x : days[i])
q.push(x);
int left = lo;
while (!q.empty() && left) {
cout << q.front() << ' ';
q.pop();
--left;
}
cout << "0\n";
}
}
