#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
//freopen("angry.in", "r", stdin);
//freopen("angry.out", "w", stdout);
int n, d, m;
cin >> n >> d >> m;
vector<pair<int, int>> v(m);
for (int i = 0; i < m; i++)
{
cin >> v[i].first;
v[i].first += d;
v[i].second = i + 1;
}
sort(v.begin(), v.end());
int l = 0, r = m + 1;
auto can = [&](int mid)
{
int pos = 0;
for (int i = 1; pos < m; i++)
{
if (v[pos].first < i) return false;
for (int j = 0; j < mid && pos < m; j++)
{
if (v[pos].first - d <= i && v[pos].first >= i) pos++;
else break;
}
}
return true;
};
while (r - l > 1)
{
int mid = (l + r) >> 1;
if (can(mid)) r = mid;
else l = mid;
}
cout << r << '\n';
int pos = 0;
for (int i = 1; i <= n; i++)
{
for (int j = 0; j < r && pos < m; j++)
{
if (v[pos].first - d <= i && v[pos].first >= i) pos++, cout << v[pos - 1].second << ' ';
else break;
}
cout << 0 << '\n';
}
return 0;
}
