#include <bits/stdc++.h>
using namespace std;
struct Job {
int pos;
int index;
Job(int p, int i) : pos(p), index(i) {}
bool operator<(const Job &other) const {
return pos < other.pos;
}
};
bool work(int num, int d, vector<Job> &array) {
int m = array.size();
int batches = (m + num - 1) / num; // ceil division
for (int i = 0; i < batches; i++) {
if (array[i * num].pos + d < i) return false;
}
return true;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, d, m;
cin >> n >> d >> m;
vector<Job> array;
for (int i = 0; i < m; i++) {
int p;
cin >> p;
array.emplace_back(p - 1, i + 1);
}
sort(array.begin(), array.end());
int l = 1, r = m;
while (l <= r) {
int mid = (l + r) / 2;
if (work(mid, d, array))
r = mid - 1;
else
l = mid + 1;
}
cout << l << "\n";
for (int i = 0; i < m; i++) {
cout << array[i].index << " ";
if ((i + 1) % l == 0)
cout << "0\n";
}
}
