#include <bits/stdc++.h>
#define ll long long
#define endl "\n"
using namespace std;
void solve()
{
ll n, d, m;
cin >> n >> d >> m;
vector<ll> v[n + 1];
ll tm[m + 1];
for (ll i = 1; i <= m; i++)
{
cin >> tm[i];
v[tm[i]].push_back(i);
}
ll l = 1, r = m;
queue<ll> q;
vector<ll> ans[n + 1];
while (l <= r)
{
ll mid = (l + r) >> 1;
bool ok = true;
while (!q.empty())
q.pop();
for (ll i = 1, cnt; i <= n; i++)
{
for (ll j : v[i])
q.push(j);
if (!q.empty() and tm[q.front()] + d < i)
{
ok = false;
break;
}
cnt = 0;
while (!q.empty() and cnt < mid)
cnt++, q.pop();
}
if (ok)
r = mid - 1;
else
l = mid + 1;
}
cout << ++r << endl;
while (!q.empty())
q.pop();
for (ll i = 1, cnt; i <= n; i++)
{
for (ll j : v[i])
q.push(j);
cnt = 0;
while (!q.empty() and cnt < r)
cout << q.front() << " ", cnt++, q.pop();
cout << "0\n";
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
ll t = 1;
// precomp();
// cin >> t;
for (ll i = 1; i <= t; i++)
solve();
cerr << "\nTime elapsed: " << clock() * 1000.0 / CLOCKS_PER_SEC << " ms\n";
}
