#include <bits/stdc++.h>
using namespace std;
bool ifPossible(vector<int>& jobs, int& x, int& d) {
deque<pair<int,int>> dq;
for(int i = 0; i < jobs.size(); i++) {
if(!dq.empty() && dq.front().first + d < i) return 0;
int machines = x;
while(!dq.empty() && machines) {
if(dq.front().second > machines) {
dq.front().second -= machines;
machines = 0;
}
else {
machines -= dq.front().second;
dq.pop_front();
}
}
if(jobs[i] > machines) dq.push_back({i, jobs[i] - machines});
}
return 1;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n, m, d;
cin >> n >> d >> m;
vector<int> jobs(n);
deque<pair<int,int>> ids;
for(int i = 0; i < m; i++) {
int x;
cin >> x;
x--;
jobs[x]++;
ids.push_back({x,i + 1});
}
sort(ids.begin(), ids.end());
int L = 0,R = m;
while(R - L > 1) {
int mid = (L + R) / 2;
if(ifPossible(jobs, mid, d)) R = mid;
else L = mid;
}
// for(auto& it : ids) cout << it.first << " " << it.second << endl;
cout << R << endl;
vector<int> output;
for(int i = 0; i < n; i++) {
int machines = R;
while(!ids.empty() && machines && ids.front().first <= i) {
machines--;
output.push_back(ids.front().second);
ids.pop_front();
}
for(int x : output) cout << x << " ";
cout << 0 << endl;
output.clear();
}
return 0;
}
