#include <algorithm>
#include <array>
#include <cstring>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#define MOD 1000000007
#define ll long long
#define INF 1e9 + 10
#define lINF 1e18 + 10
using namespace std;
ll n, d, m;
pair<ll, ll> arr[1000001];
bool check(ll x) {
ll day = 1;
ll cnt = 0;
for (ll i = 0; i < m; i++) {
if (cnt == x) {
cnt = 0;
day++;
}
if (arr[i].first + d < day) {
return false;
}
cnt++;
}
if (day > n) return false;
return true;
}
void construct(ll x) {
ll day = 1;
ll cnt = 0;
for (ll i = 0; i < m; i++) {
if (cnt == x) {
cnt = 0;
cout << 0 << '\n';
day++;
}
cout << arr[i].second << ' ';
cnt++;
}
for (; day <= n; day++) {
cout << 0 << '\n';
}
}
ll first_true(ll lo, ll hi) {
hi++;
while (lo < hi) {
ll mid = lo + (hi - lo) / 2;
if (check(mid)) {
hi = mid;
} else {
lo = mid + 1;
}
}
return lo;
}
void solve() {
cin >> n >> d >> m;
for (ll i = 0; i < m; i++) {
cin >> arr[i].first;
arr[i].second = i + 1;
}
sort(arr, arr + m);
ll ans = first_true(0, INF);
cout << ans << '\n';
construct(ans);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
while (t--) solve();
return 0;
}
