#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <unordered_map>
#define ll long long int
#define F0R(i,n) for(auto i = 0; i < (n); i++)
#define FOR(i,a,b) for(auto i = (a); i <= (b); i++)
#define ROF(i,a,b) for(auto i = (a); i >= (b); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define vv vector
#define F first
#define S second
#define pb push_back
#define vi vector<int>
using namespace std;
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n,d,m; cin >> n >> d >> m;
pii a[m+5]; FOR(i,1,m) cin >> a[i].F;
FOR(i,1,m)a[i].S = i;
sort(a+1,a+m+1);
int dayNumber = 1, jobNumber = 1, machines = 1;
while(jobNumber < m) {
if(dayNumber-a[jobNumber].F > d) {
machines++;
jobNumber = machines*(dayNumber-1)+1;
}
if(jobNumber/machines == dayNumber && jobNumber % machines == 0)++dayNumber;
jobNumber++;
}
if((machines*m) % n != 0) ++machines;
cout << machines << "\n";
jobNumber = 1;
F0R(i,n) {
F0R(j,machines) {
if(jobNumber > m) {
cout << "0\n";
goto nextDay;
} else {
cout << a[jobNumber++].S << " ";
}
}
cout << "0\n";
nextDay:;
}
}
