#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define f first
#define s second
int n, d, m;
vector<pii> subs;
bool validate(int k) {
auto submitted = subs.begin();
auto done = subs.begin();
for (int i=1; i<=n+d && done != subs.end(); i++) {
if (i - done->f > d) {
return false;
}
if (submitted->f <= i) {
submitted = upper_bound(subs.begin(), subs.end(), pii(i, m+1));
}
for (int j=0; j<k && done != submitted; j++) {
done++;
}
}
return done == submitted;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> d >> m;
int x;
for (int i=0; i<m; i++) {
cin >> x;
subs.push_back({x, i+1});
}
sort(subs.begin(), subs.end());
int lower = 1;
int upper = m;
while (lower < upper) {
int mid = lower + (upper-lower)/2;
if (validate(mid)) {
upper = mid;
} else {
lower = mid+1;
}
}
cout << upper << '\n';
auto it = subs.begin();
for (int curr = 1; curr <= n; curr++) {
for (int i=0; i<upper && it != subs.end() && it->f <= curr; i++) {
cout << it->s << ' ';
it++;
}
cout << "0\n";
}
}
