#include <bits/stdc++.h>
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int N, D, M;
std::cin >> N >> D >> M;
std::vector<std::vector<int>> a(M, std::vector<int>(2));
for (int i = 0; i < M; ++i) {
std::cin >> a[i][0];
a[i][1] = i + 1;
}
sort(a.begin(), a.end());
int lo = 1, hi = M;
while (lo < hi) {
int mi = (lo + hi) / 2;
int task = 0;
bool ok = true;
for (int i = 1; i <= N && !ok; ++i) {
int cur = 0;
if (i > a[task][0] + D)
ok = false;
while (task < M && i >= a[task][0] && i <= a[task][0] + D && cur < mi) {
task++; cur++;
}
}
if (task == M && ok)
hi = mi;
else
lo = mi + 1;
}
std::cout << lo << "\n";
int task = 0;
for (int i = 1; i <= N; ++i) {
int cur = 0;
while (task < M && i >= a[task][0] && i <= a[task][0] + D && cur < lo) {
std::cout << a[task][1] << " ";
task++, cur++;
}
std::cout << 0 << "\n";
}
return 0;
}
