#include <bits/stdc++.h>
using namespace std;
using tint = long long;
using ld = long double;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
using pi = pair<int,int>;
using pl = pair<tint,tint>;
using vi = vector<int>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vvi = vector<vi>;
using vl = vector<tint>;
using vb = vector<bool>;
#define pb push_back
#define pf push_front
#define rsz resize
#define all(x) begin(x), end(x)
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)(x).size()
#define ins insert
#define f first
#define s second
#define mp make_pair
#define DBG(x) cerr << #x << " = " << x << endl;
const int MOD = 1e9+7;
const tint mod = 998244353;
const int MX = 1e5+5;
const tint INF = 1e18;
const int inf = 2e9;
const ld PI = acos(ld(-1));
const ld eps = 1e-5;
const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, 1, -1};
template<class T> void remDup(vector<T> &v){
sort(all(v)); v.erase(unique(all(v)),end(v));
}
template<class T> bool ckmin(T& a, const T& b) {
return b < a ? a = b, 1 : 0;
}
template<class T> bool ckmax(T& a, const T& b) {
return a < b ? a = b, 1 : 0;
}
bool valid(int x, int y, int n, int m){
return (0<=x && x<n && 0<=y && y<m);
}
int cdiv(int a, int b) { return a/b+((a^b)>0&&a%b); } //redondea p arriba
int fdiv(int a, int b) { return a/b-((a^b)<0&&a%b); } //redondea p abajo
void NACHO(string name = ""){
ios_base::sync_with_stdio(0); cin.tie(0);
if(sz(name)){
freopen((name+".in").c_str(), "r", stdin);
freopen((name+".out").c_str(), "w", stdout);
}
}
vi a[MX];
int main(){
NACHO();
int n, d, m; cin >> n >> d >> m;
F0R(i, m){
int x; cin >> x;
a[x].pb(i+1);
}
int low = 0, high = 1e6+5;
while(high-low > 1){
int mid = low+(high-low)/2;
queue<int> q;
int maxi = -inf;
FOR(i, 1, n+1){
F0R(j, sz(a[i])) q.push(i);
int Mid = mid;
while(sz(q) && Mid){
auto u = q.front(); q.pop();
--Mid;
ckmax(maxi, i-u);
}
}
if(maxi <= d) high = mid;
else low = mid;
}
cout << high << "\n";
queue<int> q;
FOR(i, 1, n+1){
F0R(j, sz(a[i])) q.push(a[i][j]);
int Mid = high;
while(sz(q) && Mid){
auto u = q.front(); q.pop();
--Mid;
cout << u << " ";
}
cout << 0 << "\n";
}
}
