#include<bits/stdc++.h>
#define int ll
#define forn(i,n) for(int i=0;i<(n);i++)
#define Forn(i,n) for(int i=1;i<=(n);i++)
#define ll long long
#define pb push_back
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define rz resize
#define vi vector<int>
#define vl vector<long long>
#define vpi vector<pair<int,int> >
#define pii pair<int,int>
#define pll pair<long long,long long>
#define mp make_pair
#define all(p) p.begin(),p.end()
#define alr(p,q) p+1,p+q+1
#define ull unsigned long long
#define st0(p) memset((p),0,sizeof(p))
#define T(x) ((x)%2 ? s[(x)/2] : '.')
#define lowb(x) x&-x
#define ls(x) (x)*2
#define rs(x) (x)*2+1
using namespace std;
inline void USACO(const string &s){
freopen((s+".in").c_str(),"r",stdin);
freopen((s+".out").c_str(),"w",stdout);
}
void debug() {cout << endl;}
template <class T, class ...U> void debug(T a, U ... b) { cout << a << " "; debug(b...);}
// template <class T> int max(T a, T ... b) { cout << a << " "; debug(b...);}
#define fail() {cout << "-1\n";return;}
const int INF = 1e9+7;
const int N = 1e6+9;
int n,d,m;
vi q[N];
bool check(int x){
int cur = 1,sum = x;
Forn(i,n){
int res = q[i].size();
if(cur < i){
cur = i,sum = x;
}
while(res){
res -= sum;
// debug(cur,sum,res);
if(res < 0){
sum = -res;
res = 0;
}
cur++;
sum = x;
// debug(cur,sum,res);
if(cur > i+d) return 0;
}
}
return 1;
}
void out(int x){
int cur = 1,sum = x;
Forn(i,n){
while(cur < i){
cur++,sum=x;
cout << "0\n";
}
for(auto &j : q[i]){
cout << j << ' ';
sum--;
if(sum == 0){
cur++;
sum = x;
cout << "0\n";
}
}
}
}
void solve(){
cin >> n >> d >> m;
int tmp;
Forn(i,m){
cin >> tmp;
q[tmp].pb(i);
}
int lo = 0,hi = 2e6;
while(lo != hi-1){
int mid = (lo+hi)/2;
if(check(mid)) hi = mid;
else lo = mid;
}
cout << hi << '\n';
out(hi);
// debug(check(1),check(2),check(3));
}
signed main(){
// USACO("sabotage");
cin.tie(0);
cout.tie(0);
ios_base::sync_with_stdio(0);
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
// int t;
// cin >> t;
// while(t--)
solve();
return 0;
}
