#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define MAXN 100005
#define MAXM 1000000
int n, d, m, arr[MAXN], res = 0;
pair<int, int> req[MAXM];
int main(){
cin >> n >> d >> m;
FOR(i, 1, n) arr[i] = 0;
FOR(i, 1, m){
int x; cin >> x;
arr[x]++;
req[i - 1] = {x, i};
}
sort(req, req + m - 1);
multiset<int> s;
FOR(i, 1, 1 + d) s.insert(0);
FOR(i, 1, n){
res = max(res, *s.rbegin());
s.erase(s.find(*s.rbegin()));
s.insert(0);
FOR(j, 1, arr[i]){
int k = *s.begin();
s.erase(s.begin());
s.insert(k + 1);
}
}
res = max(res, *s.rbegin());
cout << res << endl;
int k = -1;
FOR(i, 1, n){
int j = 1;
while(j <= res && (k + 1 < m) && (req[k + 1].first <= i && i <= req[k + 1].first + d)){
cout << req[k + 1].second << " ";
j++, k++;
}
cout << "0" << endl;
}
}
