#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ordered_set <int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define ordered_multiset <int, null_type, less_equal <int>, rb_tree_tag, tree_order_statistics_node_update>
#define int long long
#define double long double
#define pii pair <int, int>
#define tiii tuple <int, int, int>
#define tiiii tuple <int, int, int, int>
#define emb emplace_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define iShowSpeed cin.tie(NULL)->sync_with_stdio(false)
#define matrix vector <vector <int>>
#define mat(n, m) vector <vector <int>> (n, vector <int> (m));
const int mod = 1e9 + 7;
const int inf = 1e18;
const matrix II = {{1, 0}, {0, 1}};
const int N = 2e5 + 5;
void solve(){
int n, d, m; cin >> n >> d >> m;
vector <int> vec[n + 1];
for (int i = 1; i <= m; i++) {
int a; cin >> a;
vec[a].emb(i);
}
int l = 1, r = m, ans = m;
while (l <= r) {
int mid = (l + r) / 2;
priority_queue <pii, vector <pii>, greater <pii>> pq;
bool ok = 1;
for (int i = 1; i <= n; i++) {
int cur = mid;
for (auto e : vec[i]) {
pq.emplace(i + d, e);
}
if (pq.size() && pq.top().first < i) {
ok = 0;
break;
}
while (!pq.empty() && cur--) {
pq.pop();
}
}
if (ok) ans = mid, r = mid - 1;
else l = mid + 1;
}
cout << ans << "\n";
priority_queue <pii, vector <pii>, greater <pii>> pq;
for (int i = 1; i <= n; i++) {
int cur = ans;
for (auto e : vec[i]) {
pq.emplace(i + d, e);
}
while (!pq.empty() && cur--) {
cout << pq.top().second << " ";
pq.pop();
}
cout << "0\n";
}
}
int32_t main(){
iShowSpeed;
// int q; cin >> q; while (q--)
solve();
}
