#include <bits/stdc++.h>
using namespace std;
int n , d , m;
vector<pair<int , int>> jobs;
//for a given number of machines, check if it works
bool valid(int machines){
priority_queue<int, vector<int> , greater<int>> endTimes;
for(int i=0; i<machines; i++){
endTimes.push(jobs[i].first);
}
for(int i=machines; i<m; i++){
int newEndTime = max(endTimes.top() + 1 , jobs[i].first);
if(newEndTime - jobs[i].first > d) return false;
endTimes.push(newEndTime);
endTimes.pop();
}
return true;
}
//we want the MINIMUM number of machines, so use first_true
int binarySearch(int lo, int hi){
hi++;
while(lo < hi){
int mid = lo + (hi - lo)/2;
if(valid(mid)){
hi = mid;
}
else{
lo = mid + 1;
}
}
return lo;
}
int main(){
//freopen("job.in" , "r" , stdin);
cin >> n >> d >> m; jobs.resize(m);
for(int i=0; i<m; i++){
cin >> jobs[i].first;
jobs[i].second = i+1;
}
sort(jobs.begin() , jobs.end());
int minMachines = binarySearch(1 , m);
cout << minMachines << endl;
vector<vector<int>> schedule(n+1);
priority_queue<int, vector<int> , greater<int>> endTimes;
for(int i=0; i<minMachines; i++){
endTimes.push(jobs[i].first);
schedule[jobs[i].first].push_back(jobs[i].second);
}
for(int i=minMachines; i<m; i++){
int newEndTime = max(endTimes.top() + 1 , jobs[i].first);
schedule[newEndTime].push_back(jobs[i].second);
endTimes.push(newEndTime);
endTimes.pop();
}
for(int i=1; i<=n; i++){
for(const int x : schedule[i]){
cout << x << " ";
}
cout << 0 << endl;
}
}
