#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
ios::sync_with_stdio(0), cin.tie(0);
int n, d, m; cin >> m >> d >> n; d--;
pair <int, int> a[n];
int id = 1;
for (auto &[x, y] : a) cin >> x, y = id++;
sort(a, a+n);
int cnt[m+1]; memset(cnt, 0, sizeof(cnt));
multiset <pair <int, int>> ms;
int L = 1, R = 0;
for (auto &[x, y] : a) {
while (R < x+d && R < m) {
R++;
ms.emplace(0, R);
}
while (L < x) {
ms.erase(ms.find(make_pair(cnt[L], L)));
L++;
}
auto [c, id] = *ms.begin();
ms.erase(ms.begin());
cnt[id]++;
ms.emplace(cnt[id], id);
}
int x = 0, it = 0, c = 0;
for (int i = 1; i <= m; i++) x = max(x, cnt[i]);
cout << x << '\n';
while (it < n) {
++c;
for (int i = 0; i < x; i++) {
if (a[it].first > c) break;
cout << a[it].second << ' ';
it++;
}
cout << 0 << '\n';
}
while (c < m) cout << 0 << '\n', c++;
}
