#include <bits/stdc++.h>
using namespace std;
int main() {
int n, d, m;
cin >> n >> d >> m;
vector<pair<int, int>> a(m);
for (int i = 0; i < m; i++) {
cin >> a[i].first;
a[i].second = i;
}
sort(a.begin(), a.end());
int lo = 1, hi = m;
while (lo < hi) {
int mid = (lo+hi)/2;
int idx = 0;
int day = 1;
bool poss = true;
while (idx < m) {
if (day > n) {
poss = false;
break;
}
for (int i = 0; i < mid && idx < m; i++) {
if (a[idx].first+d >= day) idx++;
else {
poss = false;
break;
}
}
day++;
}
if (!poss) lo = mid+1;
else hi = mid;
}
cout << hi << '\n';
int z = 0;
for (int i = 0; i < m; i += hi) {
for (int j = i; j < min(m, i+hi); j++) cout << a[j].second+1 << ' ';
cout << "0\n";
z++;
}
for (int i = z; i < n; i++) cout << "0\n";
return 0;
}
