#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define ff first
#define ss second
#define pii pair<int, int>
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n, d, m;
cin >> n >> d >> m;
pii p[m];
for (int i = 0; i < m; i++) {
cin >> p[i].ff; p[i].ff--; p[i].ss = i;
}
sort(p, p + m);
int l = 0, r = m;
vector<vector<int>> ans;
while (l <= r) {
int md = (l + r) >> 1;
int cur = 0;
vector<vector<int>> u(n);
for (int i = 0; i < m; i++) {
while (cur <= p[i].ff + d && (cur < p[i].ff || (int)u[cur].size() == md)) cur++;
if (cur > p[i].ff + d) {
cur = -1; break;
}
u[cur].push_back(p[i].ss);
}
if (!~cur) l = md + 1;
else {
ans = u;
r = md - 1;
}
}
cout << l << '\n';
for (auto i : ans) {
for (auto j : i)
cout << j + 1 << ' ';
cout << "0\n";
}
}
