// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
#include <numeric>
#include <stack>
#include <chrono>
using namespace std;
void fast_io(){
// freopen("", "r", stdin);
// freopen("", "w", stdout);
ios::sync_with_stdio(0);
cin.tie(); cout.tie();
cout << setprecision(9);
}
#define int long long
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define fi first
#define se second
void print(queue<int> Q){
while (Q.size()){
cout << Q.front() << ' ';
Q.pop();
}
cout << endl;
}
void solve() {
int n, d, m; cin >> m >> d >> n;
int a[n + 1];
map<int, int> C;
map<int, vector<int>> idx;
for (int i = 1; i <= n; i++){
cin >> a[i];
idx[a[i]].push_back(i);
C[a[i]]++;
}
int l = 0, r = m;
vector<int> ans;
while (r - l > 1){
int mid = (l + r) / 2;
queue<int> Q;
bool check = 1;
for (int i = 1; i <= m; i++){
for (int j = 0; j < C[i]; j++) Q.push({i});
int x = mid;
while (x > 0 && Q.size()){
if (i - Q.front() > d){
check = 0;
break;
}
x--;
Q.pop();
}
}
if (check && Q.empty()) {r = mid;}
else l = mid;
}
cout << r << endl;
queue<int> Q;
for (int i = 1; i <= m; i++){
for (int j = 0; j < C[i]; j++) Q.push({i});
int x = r;
while (x > 0 && Q.size()){
x--;
cout << idx[Q.front()].back() << ' ';
idx[Q.front()].pop_back();
Q.pop();
}
cout << 0 << endl;
}
return;
}
signed main() {
fast_io();
srand(chrono::steady_clock::now().time_since_epoch().count());
int tc = 1;
// cin >> tc;
while (tc--) solve();
return 0;
}
