//#include "gondola.h"
#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 1e6 + 100, M = 1e7 + 10, len = 21, inf = 1e18;
const ll mod = 1000000009LL;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll um(ll a, ll b){
return (1LL * a * b) % mod;
}
ll subr(ll a, ll b){
return ((1LL * a - b) % mod + mod) % mod;
}
int n, d, from = 0, m;
pii a[N];
queue <pii> vec;
bool check(int x){
int st = 1;
for(int i = 1; i <= n; i++){
if((int)vec.size() > 0){
if(i - vec.front().S > d) return 0;
}
while(st <= m){
if(a[st].F == i){
vec.push({a[st].S, i});
st++;
} else break;
}
int xx = x;
while(xx--){
if((int)vec.size() == 0) break;
vec.pop();
}
}
return true;
}
void make(int x){
int st = 1;
for(int i = 1; i <= n; i++){
vector <int> cur;
while(st <= m){
if(a[st].F == i){
vec.push({a[st].S, i});
st++;
} else break;
}
int xx = x;
while(xx--){
if((int)vec.size() == 0) break;
cout << vec.front().F << " ";
vec.pop();
}
cout << 0 << endl;
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> d >> m;
for(int i = 1; i <= m; i++){
cin >> a[i].F;
a[i].S = i;
}
sort(a + 1, a + 1 + m);
int l = 0, r = m;
while(r - l > 1){
int mid = (l + r) / 2;
while(vec.size() != 0){
vec.pop();
}
if(check(mid)) r = mid;
else l = mid;
}
cout << r << endl;
while(vec.size() != 0){
vec.pop();
}
make(r);
return 0;
}
