#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;//998244353
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
int N,M,D;
cin>>N>>D>>M;
vector<int>J(N+1);
vector<vector<int>>P(N+1);
for (int i = 0; i < M; i++)
{
int x;
cin>>x;
J[x]++;
P[x].push_back(i+1);
}
int lo=1;int hi=M;
int mid;
int ans=0;
while (lo<=hi)
{
mid = lo+(hi-lo)/2;
bool ok=true;
queue<pair<int,int>>q;
for (int i = 1; i <= N; i++)
{
if(J[i])q.push({J[i],i});
int left=mid;
if(!q.empty()&&i-D>q.front().second)ok=false;
while(!q.empty()&&q.front().first<=left)left-=q.front().first,q.pop();
if(!q.empty()&&q.front().first>left)q.front().first-=left;
}
if(ok){
ans=mid;
hi=mid-1;
}else{
lo=mid+1;
}
}
cout<<ans;
queue<int>what;
for (int i = 1; i <= N; i++)
{
cout<<"\n";
for (auto sd:P[i])
{
what.push(sd);
}
for (int i = 0; i < ans && !what.empty(); i++)
{
cout<<what.front()<<" ";
what.pop();
}
cout<<0;
}
return 0;
}
