#include<bits/stdc++.h>
using namespace std;
const int N = 1e6+5;
int mem[N];vector<int>a;int n,d,m,ma2=0;
bool chk(int vv){
//cout<<"This is vv : "<<vv<<"\n";
int khang = 1;
int v = vv;
for(int i=1;i<=n;i++){
//cout<<i<<"\n";
v=vv;
if(khang<i-d){
return false;
}
while(v>0){
if(mem[khang]<=v){
v-=mem[khang];
khang++;
//cout<<"khang = "<<khang<<"\n";
if(v<0)break;
if(khang>i){
break;
}
}
else{
mem[khang]-=v;
break;
}
}
}
if(khang>n)return true;
return false;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>d>>m;int ma = 0;
a.resize(m);
for(int i=0;i<m;i++){
cin>>a[i];
mem[a[i]]++;
ma=max(ma,mem[a[i]]);
ma2=max(ma2,a[i]);
}
int l=1,r=ma;
while(l<r){
int mid = (l+r)/2;
if(chk(mid)){
r=mid;
}
else l = mid+1;
}
cout<<l<<"\n";
priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> q;
for(int i=1;i<=m;i++){
q.push({a[i-1],i});
}
bool can=true;
for(int i=1;i<=n;i++){
int dd=0;
while(!q.empty() && q.top().first<=i && dd<l){
cout << q.top().second << " ";
q.pop();
dd++;
}
cout << "0\n";
}
return 0;
}
