#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef double db;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define vt vector
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define FOR(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define sz(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()
#define el '\n'
const ll N = 2e5 + 7;
const ll MOD = 1e9 + 7;
int n, d, m;
int a[N];
vt<int> v[N], ans;
bool f(int m){
deque<int> q;
FOR(i, 1, n){
if(q.size() && q.front() < i - d) return 0;
REP(j, a[i]) q.pb(i);
REP(j, m){
if(q.empty()) break;
q.pop_front();
}
// cout << i << "----\n";
// REP(i, q.size()){
// cout << q[i] << " ";
// }
// cout << el;
}
return 1;
}
void solve(){
cin >> n >> d >> m;
FOR(i, 1, m){
int x;
cin >> x;
a[x]++;
v[x].pb(i);
}
int l = 1, r = 1e6;
while(l < r){
int m = (l + r) >> 1;
if(f(m)) r = m;
else l = m + 1;
}
cout << l << el;
FOR(i, 1, n){
for(auto x:v[i]){
ans.pb(x);
}
}
int day = 1, k = 0;
for(auto x:ans){
cout << x << ' ';
k++;
if(k == l){
k = 0;
day++;
cout << "0\n";
}
}
FOR(i, day, n){
cout << "0\n";
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("test.inp","r",stdin);
freopen("test.out","w",stdout);
freopen("test.err","w",stderr);
#endif
int ts=1;
// cin>>ts;
while(ts--){
solve();
}
return 0;
}
