#include <bits/stdc++.h>
using namespace std;
using lli = int64_t;
//replace with your directory
#ifdef LOCAL
#include <C:/Coding/CP/templates/content/debug/debug.h>
#else
#define debug(...)
#endif
void solve() {
int N, D, M;
cin >> N >> D >> M;
vector <int> d(M);
for (int i = 0; i < M; ++i) {
cin >> d[i];
}
vector <int> ord(M);
iota(ord.begin(), ord.end(), 0);
sort(ord.begin(), ord.end(), [&](int i, int j){
return d[i] < d[j];
});
vector <vector <int>> ans;
auto isGood = [&](int x) -> bool {
vector <vector <int>> schedule;
for (int i = 0; i < M; ++i) {
if(schedule.empty() || (int) schedule.back().size() == x) {
schedule.emplace_back();
}
schedule.back().emplace_back(ord[i]);
}
for (int i = 0; i < (int) schedule.size(); ++i) {
for (int &v: schedule[i]) {
if (i - D >= d[v]) return false;
}
}
ans.clear();
ans = schedule;
return true;
};
int l = 0, r = M;
while (r - l > 1) {
int m = (l + r) / 2;
if (isGood(m)) r = m;
else l = m;
}
cout << r << '\n';
for (int i = 0; i < N; ++i) {
if (i < (int) ans.size()) {
for (const int &v: ans[i]) cout << v + 1 << ' ';
}
cout << "0\n";
}
}
int main() {
std::cin.tie(0)->sync_with_stdio(0);
#ifdef LOCAL
auto begin = std::chrono::high_resolution_clock::now();
#endif
int tt = 1;
while (tt--) {
solve();
}
#ifdef LOCAL
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
std::cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
#endif
return 0;
}
