#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
vector<pair<int, int>> jobs;
int n, d, m;
bool works(int mid) {
// int counter = 0;
// int day = 1;
// for (int i = 0; i < m; i++) {
// if (day <= jobs[i].first + d) {
// if (day < jobs[i].first) {
// counter = 1 % mid;
// day = jobs[i].first + (counter == 0 ? 1 : 0);
// } else {
// counter = (counter + 1) % mid;
// if (counter == 0) day++;
// }
// } else {
// return false;
// }
// }
// return (counter == 0 ? day - 1 : day) <= n;
int counter = mid;
for (int i = 0; i < m; i++) {
if ((counter / mid) <= jobs[i].first + d) {
if ((counter / mid) < jobs[i].first) {
counter = jobs[i].first * mid + 1;
} else {
counter++;
}
} else {
return false;
}
}
counter--;
return (counter / 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 = 1; i < n + 1; i++) {
if (counter == m) {
cout << 0 << endl;
continue;
}
if (jobs[counter].first <= i) {
for (int j = 0; j < lo; j++) {
if (counter == m) break;
cout << jobs[counter++].second << " ";
}
}
cout << 0 << 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;
}
