#include <bits/stdc++.h>
using namespace std;
/* ################################ */
#define pb push_back
#define FOR(i, a, n) for(int i = (a); i < (n); i++)
#define FORN(i, n) for(int i = 0; i < (n); i++)
#define SZ(x) ((int) (x).size())
#define mp(x,y) make_pair((x), (y))
#define xx first
#define yy second
#define clr clear()
#define MOD 1000000007
typedef long long ll;
/* ################################ */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsizeof-array-argument"
template<typename T>void dbg_var(T data){cout<<data<<endl;};
void dbg_vec(const vector<int>& v){FOR(i,0,(int)v.size()){cout<<v[i]<<" ";}cout<<endl;}
void dbg_varlist(const vector<pair<string, int>>& s){FOR(i, 0, (int)s.size()){cout<<s[i].first<<": "<<s[i].second<<" | ";}cout<<endl;}
template <class T, unsigned N> void dbg_arr(T (&arr)[N]){int size = sizeof(arr)/sizeof(arr[0]);FOR(i,0,size){cout<<arr[i]<<" ";}cout<<endl;}
#pragma GCC diagnostic pop
/* ################################ */
pair<int, int> jobs[1000000];
int n, d, m;
bool possible(int numMachines) {
vector<int> curWork(numMachines, 0);
FORN(i, m) {
int curMachine = i%numMachines;
curWork[curMachine] = max(curWork[curMachine]+1, jobs[i].first);
if(curWork[curMachine] - jobs[i].first > d) {
return false;
}
}
return true;
}
int main() {
//(void)! freopen("./schedule.in", "r", stdin);
//(void)! freopen("./schedule.out", "w", stdout);
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> d >> m;
FORN(i, m) {cin >> jobs[i].first; jobs[i].second = i+1;}
sort(jobs, jobs+m);
int low = 1;
int high = m;
while(low < high){
int mid = low + (high - low) / 2;
if(possible(mid)){
high = mid;
}else{
low = mid + 1;
}
}
cout << low << endl;
vector<int> curWork(low, 0);
vector<int> days[n+1];
FORN(i, m) {
int curMachine = i%low;
curWork[curMachine] = max(curWork[curMachine]+1, jobs[i].first);
days[curWork[curMachine]].push_back(jobs[i].second);
if(curWork[curMachine] - jobs[i].first > d) {
return false;
}
}
FOR(i, 1, n+1) {
for(int x : days[i]) {
cout << x << " ";
}
cout << 0 << endl;
}
return 0;
}
