#include <bits/stdc++.h>
using namespace std;
int N, D, M;
struct ValidScheduler {
bool valid;
vector<vector<int>> scheduler;
};
ValidScheduler check(int mid, vector<vector<int>> &assign) {
queue<pair<int, int>> delayed;
vector<vector<int>> schedule(N);
ValidScheduler ans;
for (int i = 0; i < N; i++) {
int numMachines = mid;
if (!delayed.empty()) {
int numRemove = min((int)delayed.size(), numMachines);
for (int j = 0; j < numRemove; j++) {
pair<int, int> delayedReq = delayed.front();
if (i - delayedReq.second > D) {
ans.valid = false;
return ans;
}
schedule[i].push_back(delayedReq.first);
delayed.pop();
numMachines--;
}
}
for (int j = 0; j < (int)assign[i].size(); j++) {
if (j < numMachines) {
schedule[i].push_back(assign[i][j]);
}
else {
delayed.push({ assign[i][j], i });
}
}
}
ans.valid = true;
ans.scheduler = schedule;
// for (int i = 0; i < N; i++) {
// for (int j = 0; j < (int)schedule[i].size(); j++) {
// cout << schedule[i][j] << ' ';
// }
// cout << 0 << '\n';
// }
return ans;
}
int main() {
cin >> N >> D >> M;
vector<vector<int>> assign(N);
for (int i = 0; i < M; i++) {
int req;
cin >> req;
req--;
assign[req].push_back(i + 1);
}
// for (int i = 0; i < N; i++) {
// cout << "Day: " << i << " , ";
// for (int j = 0; j < assign[i].size(); j++) {
// cout << assign[i][j] << ' ';
// }
// cout << '\n';
// }
vector<vector<int>> schedule(N);
int ans = 0;
int l = 1;
int r = M;
while (l <= r) {
int mid = l + (r - l) / 2;
// cout << l << ' ' << r << ' ' << mid << '\n';
if (check(mid, assign).valid) {
schedule = check(mid, assign).scheduler;
ans = mid;
r = mid - 1;
// cout << "NEXT\n";
} else {
l = mid + 1;
}
}
cout << ans << '\n';
for (int i = 0; i < N; i++) {
for (int j = 0; j < (int)schedule[i].size(); j++) {
cout << schedule[i][j] << ' ';
}
cout << 0 << '\n';
}
}
