#include <iostream>
#include <vector>
#define mp make_pair
#include <unordered_map>
#define ll long long int
#include <algorithm>
using namespace std;
ll N,D,M;
vector<pair<ll,ll> > v;
bool isok(ll k) {
ll indexi=0;
ll indexj=0;
for(ll i=0;i<M;i++) {
if(indexj==k||v[i].first>indexi+1) {
indexi++;
indexj=0;
if(indexi>=N) return false;
}
if(indexi+1-v[i].first>D) return false;
indexj++;
}
return true;
}
ll bsearch() {
ll a=1,b=1e7;
unordered_map<ll,bool> m;
while(a<=b) {
ll k=(a+b)/2;
m[k]=isok(k);
if(m[k]&&(k==1||(m.count(k-1)&&!m[k-1]))) return k;
if(!m[k]&&m.count(k+1)&&m[k+1]) return k+1;
if(m[k]) b=k-1;
else a=k+1;
}
return -1;
}
int main() {
cin>>N>>D>>M;
v.resize(M);
for(ll i=0;i<M;i++) {
cin>>v[i].first;
v[i].second=i;
}
sort(v.begin(), v.end());
ll sol=bsearch();
cout<<bsearch()<<"\n";
ll indexi=0;
ll indexj=0;
for(ll i=0;i<M;i++) {
if(indexj==sol||v[i].first>indexi+1) {
indexi++;
indexj=0;
cout<<0<<"\n";
}
cout<<v[i].second+1<<" ";
indexj++;
}
cout<<0<<'\n';
while(indexi<N-1) {
indexi++;
cout<<0<<"\n";
}
}
