#include <bits/stdc++.h>
// Author: Kazuki_Will_Win_VOI_8703
#define fi first
#define se second
#define pii pair<int, int>
#define int long long
#define all(a) a.begin(), a.end()
using namespace std;
const int mn = 1e6 + 5;
int n, d, m, cnt[mn];
vector <pii> Megumi;
bool check(int mid){
int left = mid, Reina = 1;
for(int day = 1; day <= n; day++){
if(Reina < day) Reina = day, left = mid;
if(cnt[day] <= left) left -= cnt[day];
else{
int extra = cnt[day] - left;
int add = (extra + mid - 1) / mid;
Reina += add;
left = add * mid - extra;
if(Reina > day + d) return false;
}
}
if(Reina > n) return false;
return true;
}
void solve(){
cin >> n >> d >> m;
int r = 0;
for(int i = 1; i <= m; i++){
int x; cin >> x;
Megumi.push_back({x, i});
cnt[x] ++;
r = max(r, cnt[x]);
}
int l = 1, ans = -1;
sort(all(Megumi));
while(l <= r){
int mid = (l + r) >> 1;
if(check(mid)){
r = mid - 1;
ans = mid;
}
else l = mid + 1;
}
cout << ans << '\n';
int left = ans, Reina = 1;
for(auto [day, i] : Megumi){
while(Reina < day){
cout << 0 << '\n';
left = ans;
Reina ++;
}
if(left == 0){
cout << 0 << '\n';
Reina ++, left = ans;
}
cout << i << ' ';
left --;
}
while(Reina <= n){
cout << 0 << '\n';
Reina ++;
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
// cin >> t;
while(t--){
solve();
}
}
