#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10, M = 1e6+10;
int n, k, m;
vector<int> a[N];
vector<int> ans[N];
int day[M];
bool chk(int mid){
int cur = 1, mac = 1;
for(int i = 1; i <= n; ++i){
if(cur < i) cur = i, mac = 1;
for(int x : a[i]){
if(cur > i+k) return false;
if(mac == mid) cur++, mac = 1;
else mac++;
}
}
return true;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> k >> m;
for(int i = 1; i <= m; ++i){
int x; cin >> x;
a[x].push_back(i);
}
int l = 1, r = M;
while(l < r){
int mid = (l+r)>>1;
if(chk(mid)) r = mid;
else l = mid+1;
}
cout << l << '\n';
int cur = 1, mac = 1;
for(int i = 1; i <= n; ++i){
if(cur < i) cur = i, mac = 1;
for(int x : a[i]){
day[x] = cur;
if(mac == l) cur++, mac = 1;
else mac++;
}
}
for(int i = 1; i <= m; ++i){
ans[day[i]].push_back(i);
}
for(int i = 1; i <= n; ++i){
for(int x : ans[i]) cout << x << ' ';
cout << 0 << '\n';
}
cout << '\n';
}
