#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, d, m;
cin >> n >> d >> m;
vector<pair<int, int>> a(m);
for (int i = 0; i < m; i++) {
int x;
cin >> x;
a[i] = {x, i};
}
sort(a.begin(), a.end());
auto check = [&](int k) {
queue<int> q;
int i = 0;
for (int day = 1; day <= n; day++) {
while (i < m && a[i].first == day) {
q.push(a[i++].first);
}
for (int j = 0; j < k; j++) {
if (q.empty()) {
break;
}
if (day - q.front() > d) {
return 0;
}
q.pop();
}
}
return 1;
};
int lo = 1, hi = m;
while (lo <= hi) {
int mid = (lo + hi) >> 1;
if (check(mid)) {
hi = mid - 1;
} else {
lo = mid + 1;
}
}
cout << hi + 1 << '\n';
queue<int> q;
int i = 0;
for (int day = 1; day <= n; day++) {
while (i < m && a[i].first == day) {
q.push(a[i++].second);
}
for (int j = 0; j < hi + 1; j++) {
if (q.empty()) {
break;
}
cout << q.front() + 1 << ' ';
q.pop();
}
cout << 0 << '\n';
}
return 0;
}
