// https://oj.uz/problem/view/CEOI12_jobs
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(0);
#define FASTIOF ios_base::sync_with_stdio(false); fin.tie(0);
#define mp make_pair
#define f first
#define s second
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
#define lb lower_bound
#define ub upper_bound
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
template<class T> void remDup(vector<T>& v) { sor(v); v.erase(unique(all(v)), v.end()); }
const int MOD = 1e9 + 7;
const int MX = 1e6 + 10;
const ll INF = 1e18;
int N, D, M; vpi A;
bool valid(int numMachine, bool P) {
int curDay = 1, cnt = 0;
while (cnt < M) {
int curMachineUsed = 0;
while (cnt < M && curMachineUsed < numMachine && A[cnt].f <= curDay) {
if (A[cnt].f < curDay - D) {
return false;
}
if (P) {
cout << A[cnt].s << " ";
}
curMachineUsed++, cnt++;
}
if (P) cout << "0" << "\n";
curDay++;
}
if (P) {
FOR(i, curDay, N + 1) {
cout << "0" << "\n";
}
}
return true;
}
int main() {
FASTIO;
cin >> N >> D >> M;
FOR(i, 1, M + 1) {
int X; cin >> X;
A.pb({X, i});
}
sor(A);
int low = 1; int high = M; int res = -1;
while (low <= high) {
int mid = (low + high) / 2;
if (valid(mid, false)) {
res = mid, high = mid - 1;
}
else {
low = mid + 1;
}
}
cout << res << "\n";
valid(res, true);
}
