#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
int ans=0;
void to_ternary(int n){
if(n==0)return ;
int x=n%3;
ans+=x;
n/=3;
to_ternary(n);
}
signed main(){
ios_base::sync_with_stdio();
cin.tie(0);cout.tie(0);
int n,d,m;
cin>>n>>d>>m;
vector <pair <int,int> > v;
for(int i=1;i<=m;i++){
int x;cin>>x;
v.pb({x,i});
}
sort(all(v));
int l=0;
int r=10;
while(l+1<r){
int md=(l+r)/2;
deque <int> day;
for(auto x : v){
day.pb(x.ff);
}
for(int i=1;i<=n;i++){
int cnt=md;
while(day.size()!=0 && day.front()>=i-d && day.front()<=i && cnt>0){
day.pop_front();
cnt--;
}
}
if(day.size()==0)r=md;
else l=md;
}
deque <int> day,ind;
for(auto x : v){
day.pb(x.ff);
ind.pb(x.ss);
}
vector <vector <int> > ans(n+1);
cout<<r<<"\n";
for(int i=1;i<=n;i++){
int cnt=r;
while(day.size()!=0 && day.front()>=i-d && day.front()<=i && cnt>0){
day.pop_front();
ans[i].pb(ind.front());
ind.pop_front();
cnt--;
}
ans[i].pb(0);
}
for(int i=1;i<=n;i++){
for(auto x : ans[i])cout<<x<<" ";
cout<<"\n";
}
}
/*
8 2 12
1 2 4 2 1 3 5 6 2 3 6 4
*/
