/*input
8 2 12
1 2 4 2 1 3 5 6 2 3 6 4
*/
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
const int N=1e6 + 100;
#define pii pair<int, int>
#define f first
#define s second
#define mp make_pair
pii arr[N];int n, m, d, oriarr[N];//vector<int> days[N];
bool final;
bool p(int x){
int ptr=1;
for(int i=1;i<=n;i++)
{
int ct=0;
while(ptr<=m&&arr[ptr].f<=i&&ct<x)
{
if(arr[ptr].f+d>=i) ptr++;
else return false;
if(final) cout<<arr[ptr-1].s<<" ";
ct++;
}
if(final) cout<<0<<endl;
}
if(ptr<=m) return false;
return true;
}
bool sf(pii a, pii b){
return a.f<b.f;
}
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
cin>>n>>d>>m;
for(int i=1;i<=m;i++)
{
cin>>arr[i].f;arr[i].s=i;oriarr[i]=arr[i].f;
}
sort(arr+1, arr+m+1, sf);
int low=1, high=m;
final=0;
while(low<high)
{
int mid=(low+high)/2;
if(p(mid)) high=mid;
else low=mid+1;
}
final=1;
cout<<low<<endl;
p(low);
}
