#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
int n, d, m;
cin >> n >> d >> m;
pair<int, int> a[m + 1];
for (int i = 1;i <= m;i++) {
cin >> a[i].f;
a[i].s = i;
}
sort(a + 1, a + m + 1);
int l = 1, r = m, ans = 0;
auto check = [&](int mid) {
int t = 0, s = 1;
for (int i = 1;i <= m;i++) {
t += 1;
if (t > mid) {
s += 1;
t = 1;
}
if (s < a[i].f) {
s = a[i].f;
t = 1;
}
if (a[i].f + d < s)
return false;
}
return true;
};
while (l <= r) {
int mid = (l + r) / 2;
if (check(mid)) {
ans = mid;
r = mid - 1;
}
else
l = mid + 1;
}
cout << ans << '\n';
for (int i = 1;i <= n;i++) {
if (i > n - d) {
cout << 0 << '\n';
continue;
}
for (int j = 1;j <= ans + 1;j++)
cout << 0 << ' ';
cout << '\n';
}
}
return 0;
}
