#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n, d, m;
bool sort2(pair<ll,ll>a,pair<ll,ll>b) {
return a.second < b.second;
}
bool val(ll machines, pair<ll,ll> a[]) {
map<ll,ll> ma;
ma.insert({0, machines});
pair<ll,ll> val;
for (ll i{0}; i < m; ++i) {
auto search = ma.upper_bound(a[i].first+d);
val = *prev(search);
if (search == ma.begin()) {
return 0;
} else {
prev(search)->second = val.second - 1;
if (val.second == 1) {
ma.erase(prev(search));
}
++ma[max(val.first, a[i].first)+1];
}
}
return 1;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> d >> m;
pair<ll,ll> a[m];
for (ll i{0}; i < m; ++i) {
cin >> a[i].first;
a[i].second = i;
}
sort(a,a+m);
ll l{1}, r{m}, ans{-1};
while (l <= r) {
ll m{(l+r)/2};
if (val(m, a)) {
r = m - 1;
ans = m;
} else {
l = m + 1;
}
}
cout << ans << "\n";
set<pair<ll,ll>> s;
for (ll i{0}; i < m; ++i) {
s.insert(a[i]);
}
for (ll i{0}; i < n; ++i) {
ll mecuse{0};
while (!s.empty() && mecuse < ans && s.begin()->first <= i + 1) {
cout << s.begin()->second+1 << " ";
s.erase(s.begin());
++mecuse;
}
cout << "0\n";
}
return 0;
}
