#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
vector<pair<int, int>> jobs;
int n, d, m;
bool works(int mid) {
int counter = 3;
for (int i = 0; i < m; i++) {
if ((counter / mid) <= jobs[i].first + d) {
counter++;
} else {
return false;
}
}
return ((counter - 1) / mid) <= n;
}
int main() {
// freopen("jobscheduling.in", "r", stdin);
cin >> n >> d >> m;
jobs = vector<pair<int, int>>(m);
for (int i = 0; i < m; i++) {
cin >> jobs[i].first;
jobs[i].second = i + 1;
}
sort(jobs.begin(), jobs.end());
int lo = 1;
int hi = 1000000;
while (lo != hi) {
int mid = (lo + hi) / 2;
if (works(mid)) {
hi = mid;
} else {
lo = mid + 1;
}
}
cout << lo << endl;
int counter = 0;
for (int i = 0; i < n; i++) {
if (counter < m)
for (int j = 0; j < lo; j++) {
if (counter < m) // cout << 0 * (counter++) << " ";
cout << jobs[counter++].second << " ";
else
break;
}
cout << 0 << endl;
}
return 0;
}
