#include <bits/stdc++.h>
using namespace std;
int n; int d; int m;
bool check(int x,vector<pair<int,int>>& jobs) {
int j = 0;
int maxdelay = 0;
for(int i=1;i<=n;i++) {
int machines = x;
while(j<m&&jobs[j].first<=i&&machines>0) {
machines--;
maxdelay = max(maxdelay,i-jobs[j].first);
j++;
}
}
return maxdelay <= d;
}
int main() {
cin >> n >> d >> m;
vector<pair<int,int>> jobs(m,make_pair(0,0));
for(int i=0;i<m;i++) {
cin >> jobs[i].first;
jobs[i].second = i+1;
}
sort(jobs.begin(),jobs.end());
int l = 1;
int r = 100000;
while(l<r) {
int mid = (l+r)/2;
if(mid==l||mid==r) {
break;
}
if(check(mid,jobs)) {
r = mid;
} else {
l = mid;
}
}
if(check(l,jobs)) {
int j = 0;
cout << l << endl;
for(int i=1;i<=n;i++) {
int machines = l;
while(j<m&&jobs[j].first<=i&&machines>0) {
machines--;
cout << jobs[j].second << " ";
j++;
}
cout << 0 << endl;
}
} else {
int j = 0;
cout << r << endl;
for(int i=1;i<=n;i++) {
int machines = r;
while(j<m&&jobs[j].first<=i&&machines>0) {
machines--;
cout << jobs[j].second << " ";
j++;
}
cout << 0 << endl;
}
}
}
