#include<bits/stdc++.h>
using namespace std;
using ll = long long;
vector<int> bucket[100100];
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int n, d, m;
cin >> n >> d >> m;
for (int i = 1;i <= m;i++) {
int x;
cin >> x;
bucket[x].push_back(i);
}
int l = 1, r = m;
while (l < r) {
int mid = (l + r) / 2;
bool ch = 1;
queue<int> q;
for (int i = 1;i <= n;i++) {
if (!q.empty() && q.front() + d < i) {
ch = 0;
break;
}
for (int j = 0;j < (int)bucket[i].size();j++)
q.push(i);
for (int j = 1;j <= mid && !q.empty();j++) q.pop();
}
if (ch && q.empty()) r = mid;
else l = mid + 1;
}
cout << l << '\n';
queue<int> q;
for (int i = 1;i <= n;i++) {
for (auto& x : bucket[i]) q.push(x);
for (int j = 1;j <= l && !q.empty();j++) {
cout << q.front() << ' ';
q.pop();
}
cout << "0\n";
}
return 0;
}
