#include <bits/stdc++.h>
using namespace std;
bool schedule(vector<int> requests, int n, int d, int m, int a) {
bool ans = true;
int counter;
for (int i=0;i<n;i++) {
counter = 0;
while (counter < a && requests.size() > 0 && requests[requests.size() - 1] < i + 2) {
counter++;
if (requests[requests.size() - 1] > i + d + 1) {
ans = false;
break;
}
requests.pop_back();
}
if (!ans) {
break;
}
}
if (requests.size() > 0) {
ans = false;
}
return ans;
}
int main() {
int n, d, m; cin >> n >> d >> m;
vector<int> requests(m);
vector<vector<int>> requestmapper(n + 1);
for (int i=0;i<m;i++) {
cin >> requests[i];
requestmapper[requests[i]].push_back(i + 1);
}
sort(requests.begin(), requests.end(), greater<int>());
int top = m, bottom = 0, middle;
while (top > bottom + 1) {
middle = (top + bottom) / 2;
if (schedule(requests, n, d, m, middle)) {
top = middle;
} else {
bottom = middle;
}
}
int counter, temp;
cout << top << '\n';
for (int i=0;i<n;i++) {
counter = 0;
while (counter < top && requests.size() > 0 && requests[requests.size() - 1] < i + 2) {
temp = requests[requests.size() - 1];
counter++;
cout << requestmapper[temp][requestmapper[temp].size() - 1] << ' ';
requestmapper[temp].pop_back();
requests.pop_back();
}
cout << 0 << '\n';
}
}
