#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
const int N=1e5+10;
int n,d,m,i,a[N],l,r,mid,res;
vector<pair<int,int>>v;
bool check(int x) {
priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>>hc;
int j=0;
for (int i=1; i<=n; i++) {
while (j<v.size() && v[j].fi==i) {
hc.push({v[j].fi+d,v[j].se});
j++;
}
for (int k=1; k<=x; k++) {
if (hc.empty()) break;
if (hc.top().fi<i) return false;
hc.pop();
}
}
return hc.empty();
}
signed main () {
cin>>n>>d>>m;
for (i=1; i<=m; i++) {
cin>>a[i];
v.push_back({a[i],i});
}
sort(v.begin(),v.end());
l=1,r=m;
while(l<=r) {
mid=(l+r)/2;
if (check(mid)) {
res=mid;
r=mid-1;
}
else
l=mid+1;
}
cout<<res<<"\n";
priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>>pq;
int j=0;
for (i=1; i<=n; i++) {
while (j<v.size() && v[j].fi==i) {
pq.push({v[j].fi+d,v[j].se});
j++;
}
int cnt=0;
while (!pq.empty() && cnt<res) {
auto t=pq.top();
pq.pop();
cout<<t.se<<" ";
cnt++;
}
cout<<0<<"\n";
}
}
