#include <bits/stdc++.h>
#define pb push_back
#define all(x) x.begin(), x.end()
#define F first
#define S second
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef pair<ll, ll> pll;
typedef string str;
const ll MOD = 1e9 + 7;
const ll N = 1e6 + 10;
const ll INF = 1e18;
ll n, d, m;
pll a[N];
bool isval(ll x){
queue <pll> q;
ll pnt = 1;
//cout << x << '\n';
for (int i = 1; i <= n; i++){
if (pnt != m + 1){
while ((pnt != m + 1) && (a[pnt].F == i)) q.push(a[pnt]), pnt ++;
}
//cout << i << ' ' << pnt << ' ' << q.size() << ' ' << x << ' ';
for (int j = 0; j < x; j++){
if (q.size() == 0) break;
q.pop();
}
//cout << q.size() << '\n';
if (q.size() != 0){
if (q.front().F + d < i + 1){
return 0;
}
}
}
if (q.size()) return 0;
return 1;
}
int main(){
cin >> n >> d >> m;
for (int i = 1; i <= m; i++){
ll v;
cin >> v;
a[i] = {v, i};
}
sort(a + 1, a + m + 1);
ll l = 0, r = INF;
while (r - l > 1){
ll mid = (l + r) / 2;
//cout << l << ' ' << r << '\n';
if (isval(mid)) r = mid;
else l = mid;
}
cout << r << '\n';
ll x = r;
queue <pll> q;
ll pnt = 1;
for (int i = 1; i <= n; i++){
if (pnt != m + 1){
while ((pnt != m + 1) && (a[pnt].F == i)) q.push(a[pnt]), pnt ++;
}
//cout << i << ' ' << pnt << ' ' << q.size() << ' ' << x << ' ';
for (int j = 0; j < x; j++){
if (q.size() == 0) break;
cout << q.front().S << ' ';
q.pop();
}
cout << 0 << '\n';
//cout << q.size() << '\n';
if (q.size() != 0){
if (q.front().F + d < i + 1){
return 0;
}
}
}
return 0;
}
/*8 2 12
1 2 4 2 1 3 5 6 2 3 6 4*/
