#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
int n, m, d, a[1000005], b[100005];
vector<int> dn[100005];
bool f(int x, bool is) {
queue<int> p;
for(int i = 1; i <= n; ++i) {
int o = x;
while(!p.empty() && o > 0) {
if(i - p.front() > d)
return 0;
--o;
if(is)
cout << dn[p.front()].back() << " ", dn[p.front()].pop_back();
p.pop();
}
for(int j = 0; j < b[i]; ++j) {
if(o > 0) {
--o;
if(is)
cout << dn[i].back() << " ", dn[i].pop_back();
continue;
}
p.push(i);
}
if(is)
cout << 0 << endl;
}
if(p.size() > 0)
return 0;
return 1;
}
int main() {
cin >> n >> d >> m;
for(int i = 0; i < m; ++i)
cin >> a[i], ++b[a[i]], dn[a[i]].push_back(i + 1);
int lo = 1, hi = 1000005;
while(lo < hi) {
int md = (hi + lo) / 2;
if(f(md, 0))
hi = md;
else
lo = md + 1;
}
cout << lo << endl;
f(lo, 1);
return 0;
}
