#include "bits/stdc++.h"
using namespace std;
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
#define int long long
#define ll __int128
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
ll read() { // read int128
int x; cin >> x; return (ll)x;
}
long long bm(long long b, long long p) {
if(p==0) return 1 % MOD;
long long r = bm(b, p >> 1);
if(p&1) return (((r*r) % MOD) * b) % MOD;
return (r*r) % MOD;
}
long long inv(long long b) {
return bm(b, MOD-2);
}
long long f[MAXN];
long long nCr(int n, int r) {
long long ans = f[n]; ans *= inv(f[r]); ans %= MOD;
ans *= inv(f[n-r]); ans %= MOD; return ans;
}
void precomp() {
for(int i=0; i<MAXN; i++) f[i] = (i == 0 ? 1 % MOD : (f[i-1] * i) % MOD);
}
void solve(int tc) {
int n, d, m;
cin >> n >> d >> m;
vector<int> a[n+1];
for(int i=1; i<=m; i++) {
int p;
cin >> p;
a[p].push_back(i);
}
int lb = 1, rb = 1e9;
while(lb < rb) {
int mid = (lb + rb) >> 1;
queue<pair<int, int> > jobs;
bool ok = 1;
for(int i=1; i<=n; i++) {
for(int x: a[i]) jobs.push({x, i});
for(int j=1; j<=mid; j++) {
if(jobs.size()) {
ok &= (i - jobs.front().second <= d);
jobs.pop();
}
else break;
}
}
if(ok) {
rb = mid;
}
else {
lb = mid + 1;
}
}
vector<int> fuck[n+1];
queue<pair<int, int> > jobs;
for(int i=1; i<=n; i++) {
for(int x: a[i]) jobs.push({x, i});
for(int j=1; j<=lb; j++) {
if(jobs.size()) {
fuck[i].push_back(jobs.front().first);
jobs.pop();
}
else break;
}
}
cout << lb << "\n";
for(int i=1; i<=n; i++) {
for(int x: fuck[i]) cout << x << " ";
cout << "0\n";
}
}
int32_t main(){
precomp();
ios::sync_with_stdio(0); cin.tie(0);
int t = 1; //cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
