#include <bits/stdc++.h>
using namespace std;
const int SIZE = 1e5 + 5;
int n,d,m;
vector<pair<int,int>> vec;
int jobs[SIZE];
queue<pair<int,int>> q;
bool solve(int k) {
int av = k;
for (int i=1; i<=n; i++) {
av = k;
if (jobs[i] > 0) q.push(make_pair(jobs[i], i+d));
while (av > 0 && !q.empty()) {
if (q.front().second < i) return 0;
else {
if (av >= q.front().first) {
av -= q.front().first;
q.pop();
}
else q.front().first -= av, av = 0;
}
}
}
return 1;
}
bool comp(pair<int,int> a, pair<int,int> b) {
return (a.first != b.first ? a.first < b.first : a.second < b.second);
}
void print(int ans) {
sort(vec.begin(), vec.end(), comp);
int left = ans, index = 0;
for (int i=1; i<=n; i++) {
left = ans;
while (index < m && vec[index].first <= i && left > 0) {
cout << vec[index].second << " ";
left --, index ++ ;
}
cout << 0 << endl;
}
return;
}
int main() {
int cur;
cin >> n >> d >> m;
for (int i=0; i<m; i++) {
cin >> cur;
vec.push_back(make_pair(cur, i+1));
jobs[cur] ++;
}
int lp = 1, rp = m;
while (lp < rp) {
int mid = lp + (rp - lp)/2;
if (solve(mid)) rp = mid;
else lp = mid + 1;
}
cout << lp << endl;
print(lp);
return 0;
}
