#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
using namespace std;
#define int long long
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, d, q;
cin >> n >> d >> q;
vector<vector<int>> day(n + 5), sol;
for (int i = 1; i <= q; i++) {
int x;
cin >> x;
day[x].push_back(i);
}
int l = 1, r = q, ans = q;
while (l <= r) {
int m = (l + r)/2;
vector<vector<int>> res(n + 5);
queue<pair<int, int>> pq;
bool possible = true;
for (int i = 1; i <= n; i++) {
int machine = m;
for (auto &v : day[i]) pq.push({i, v});
while (machine && pq.size()) {
int st = pq.front().first, indx = pq.front().second;
pq.pop();
if (i - st > d) possible = false;
res[i].push_back(indx);
machine--;
}
}
if (possible && pq.empty()) ans = m, r = m - 1, sol = res;
else l = m + 1;
}
cout << ans << '\n';
for (int i = 1; i <= n; i++) {
for (auto &v : sol[i]) cout << v << ' ';
cout << 0 << '\n';
}
return 0;
}
