#include <bits/stdc++.h>
using namespace std;
const int M=1e6+12;
int n,d,m;
pair<int,int>a[M];
bool good(int num) {
int i=0;
int day=1;
int cnt=0;
while(i<m){
if(cnt==num){
cnt=0;
day++;
}
if(a[i].first>day){
day=a[i].first;
cnt=0;
}
else if(a[i].first+d<day){
return false;
}
i++;
cnt++;
}
return day<=n;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>d>>m;
for(int i=0;i<m;i++){
cin>>a[i].first;
a[i].second=i;
}
sort(a,a+m);
int l=1;
int r=m;
int mid=(l+r)/2;
while(l<r){
mid=(l+r)/2;
if(good(mid)){
r=mid;
}
else{
l=mid+1;
}
}
int cnt=0;
cout<<l<<"\n";
int days=1;
for(int i=0;i<m;i++){
if(a[i].first<=days){
cout<<a[i].second+1<<" ";
cnt++;
if(cnt==l){
cout<<0<<"\n";
cnt=0;
days++;}}
else{
cout<<0<<"\n";
days++;
cnt=0;
}
}
for(int i=days;i<=n;i++){
cout<<0<<"\n";
}
return 0;
}
