#include<bits/stdc++.h>
#define S second
#define dbg(v) cerr << #v << " = " << v << "\n"
#define F first
#define fall(i,a,n) for(int i=a;i<=n;i++)
#define ll long long
#define pb push_back
#define all(x) x.begin(),x.end()
#define lsb(x) (x & -x)
const int MAXN=1e5+10;
const ll inf=0X3f3f3f3f3f3f3f3f;
const int infi=0X3f3f3f3f;
const ll MOD=998244353;
using namespace std;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef tuple<ll,ll,ll,ll> trio;
int n,d,m,ans;
vector<pii> v;
vector<int> aux[MAXN];
bool test(int x){
queue<int> fila;
int l=0,r=1,q=1;
while(r<=n){
while(l<m && v[l].F<=r){
fila.push(v[l].F);
l++;
}
while(!fila.empty() && q<=x){
auto u=fila.front();
if(r-u>d)
return false;
fila.pop();
q++;
}
r++;
q=1;
}
if(!fila.empty())
return false;
return true;
}
void f(int x){
queue<pii> fila;
int l=0,r=1,q=1;
while(r<=n){
while(l<m && v[l].F<=r){
fila.push({v[l].F,v[l].S});
l++;
}
while(!fila.empty() && q<=x){
auto u=fila.front();
fila.pop();
aux[r].pb(u.S);
q++;
}
r++;
q=1;
}
fall(i,1,n){
for(auto u:aux[i])cout<<u<<" ";
cout<<"0\n";
}
}
int32_t main(){
std::ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen("angry.in","r",stdin);
//freopen("angry.out","w",stdout);
cin>>n>>d>>m;
v.resize(m);
fall(i,0,m-1){
cin>>v[i].F;
v[i].S=i+1;
}
sort(all(v));
int ini=0,fim=m;
while(ini<=fim){
int mei=(ini+fim)/2;
if(test(mei)){
ans=mei;
fim=mei-1;
}
else ini=mei+1;
}
cout<<ans<<"\n";
f(ans);
}
