#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define pb push_back
#define ins insert
//cout<<fixed<<setprecision(3); 3 decimalke brez fixed pa 3 zanesljiva mesta
const int MAXN=2e5+2;
const long long linf=1e18;
const int inf=1e9;
const int mod=1e9+7;
void solve(){
int n,d,m;cin>>n>>d>>m;
vector<pair<int,int>>a(m);
for(int i=0;i<m;i++){
cin>>a[i].first;
a[i].second=i+1;
}
sort(a.begin(),a.end());
queue<int>temp;
for(auto p:a){
temp.push(p.first+d);
}
/*
auto f=[&](int mid)->bool{
queue<int>q=temp;
int e=0;
for(int i=1;i<=n;i++){
e=0;
while(e<mid&&q.size()&&q.front()-d<=i){
if(q.front()>i) return false;
q.pop();
}
}
return true;
};*/
int l=1;int r=m;int ans=1;
while(l<=r){
int mid=l+(r-l)/2;
//cout<<mid<<endl;
bool ok=true;
queue<int>q=temp;
int e=0;
for(int i=1;i<=n;i++){
e=0;
while(e<mid&&q.size()&&q.front()-d<=i){
if(q.front()<i) {
//cout<<i<<' '<<q.front()<<' '<<e<<endl;
ok=false;
break;
};
e++;
q.pop();
}
}
if(ok){
ans=mid;
r=mid-1;
}
else {
l=mid+1;
}
}
cout<<ans<<endl;
l=0;int t=0;
for(int i=1;i<=n;i++){
t=0;
while(t<ans&&l<m&&a[l].first<=i){
t++;
cout<<a[l].second<<' ';
l++;
}
cout<<0<<endl;
}
}
int main(){
std::ios::sync_with_stdio(false);
std::cin.tie(NULL);
int t=1;
while(t--) solve();
}
