#include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define MOD1 998244353
#define INF 1e18
#define inf 1e9+5
#define nl "\n"
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define clr(a) memset((a),0,sizeof(a))
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
typedef vector<int> vi;
typedef pair<int,int> pi;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key
#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif
void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}
template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
bool valid(int x, int n, vi a, int d){
for(int i=1; i<=n; i++){
a[i]=max(0, a[i]-x);
// cout<<a[i]<<" ";
if(a[i]/d > x) return false;
a[i+1]+=a[i];
}
return a[n]==0;
}
void solve(){
int n, d, m;
cin>>n>>d>>m;
vi v(m);
vi a(n+1, 0);
vector<int> q[n+1];
for(int i=0; i<m; i++){
cin>>v[i];
a[v[i]]++;
q[v[i]].pb(i+1);
}
// for(int i=1; i<=n; i++){
// cout<<a[i]<<" ";
// }
// cout<<nl;
// cout<<valid(1, n, a, d);
int lo=1, hi=1e6+10;
while(hi-lo>1){
int mid = (lo+hi)/2;
if(valid(mid,n,a,d)) hi=mid;
else lo=mid+1;
}
int ans=0;
if(valid(lo,n,a,d)){ cout<<lo; ans=lo;}
else {cout<<hi; ans=hi;}
cout<<nl;
queue<int> qq;
for(int i=1; i<n+1; i++){
for(int j=0; j<q[i].size(); j++){
qq.push(q[i][j]);
}
}
int ct=0, count=0;
while(!qq.empty()){
count++;
while(ct!=ans && !qq.empty()){
ct++;
cout<<qq.front()<<" ";
qq.pop();
}
cout<<"0\n";
ct=0;
}
count=n-count;
while(count--) cout<<"0\n";
}
int main() {
#ifndef ONLINE_JUDGE
freopen("Error.txt", "w", stderr);
#endif
ios_base::sync_with_stdio(false);
cout.tie(nullptr);
int t=1;
// cin>>t;
while(t--){
solve();
// cout<<nl;
}
}
