#include <bits/stdc++.h>
#pragma GCC target("lzcnt,popcnt")
#pragma GCC optimize("O3,unroll-loops")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define all(x) x.begin(),x.end()
#define sp << " " <<
using namespace std;
const int inf = 2e18;
const int N = 2e5+1;
void solve() {
int n,d,m;
cin >> n >> d >> m;
vector<pii> v;
for (int i=1;i<=m;i++){
int x;
cin >> x;
v.push_back({x,i});
}
sort(all(v));
reverse(all(v));
vector<pii> vv = v;
auto check = [&](int mach,int construct) -> bool {
v = vv;
if (construct) cout << mach << '\n';
for (int i = 1;i<=n;i++) {
int sz = v.size();
for (int j = 0;j<min(sz,mach);j++) {
if (v.back().ff+d <= i) return 0;
if (construct) cout << v.back().ss << ' ';
v.pop_back();
}
if (construct) cout << "0\n";
}
if (!v.empty()) return 0;
return 1;
};
int l = 0;
int r = m;
while (l<=r) {
int m = (l+r) >> 1;
if (check(m,0)) r = m-1;
else l = m+1;
}
check(l,1);
}
signed main() {
ios_base::sync_with_stdio(0);cin.tie(0);
#ifdef Dodi
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
