#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define all(v) v.begin(), v.end()
#define pb push_back
#define ss second
#define ff first
#define vt vector
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int, int> pii;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const int inf = 1e9;
const int mod = 1e9+7;
const int maxn = 1e5 + 2;
int cnt[maxn];
int ls[maxn], a[1000000];
void solve() {
int n, d, m;
cin >> n >> d >> m;
for(int i = 0; i < m; i++){
int x;
cin >> x;
a[i] = ls[x];
ls[x] = i;
cnt[x]++;
}
int l = -1, r = 1000001;
while(l + 1 < r){
bool ok = 1;
int mid = l + (r - l) / 2, xl = 1, ex = 0;
for(int i = 1; i <= n; i++){
if(i - xl > d){
ok = 0;
break;
}
ex += mid;
while(xl <= i && cnt[xl] <= ex){
ex -= cnt[xl];
xl++;
}
if(xl > i)ex = 0;
}
if(ok)r = mid;
else l = mid;
}
cout << r << '\n';
int xl = 1, ex = 0;
for(int i = 1; i <= n; i++){
ex = r;
while(ex){
while(xl <= i && cnt[xl] == 0)xl++;
if(xl > i)break;
cout << 1 + ls[xl] << ' ';
ex--;
ls[xl] = a[ls[xl]];
cnt[xl]--;
}
cout << "0\n";
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int times = 1;
//cin >> times;
for(int i = 1; i <= times; i++) {
solve();
}
return 0;
}
