#include <bits/stdc++.h>
using namespace std;
#define ld long double
#define ll long long
#define eb emplace_back
const int inf = 1e9;
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, d, m;
cin >> n >> d >> m;
vector<vector<int>>v(n + 1);
for(int i = 1; i <= m; ++i){
int x;
cin >> x;
v[x].push_back(i);
}
int l = 1, r = m;
while(l < r){
int mid = (l + r) >> 1;
queue<array<int,2>>q;
int f = 1;
for(int i = 1; i <= n; ++i){
for(int x : v[i]){
q.push({x, i});
}
int k = mid;
while (!q.empty() && k--) q.pop();
if(!q.empty() && q.front()[1] + d == i){
f = 0;
break;
}
}
f &= q.empty();
if(f){
r = mid;
}else{
l = mid + 1;
}
}
cout << l << endl;
queue<array<int,2>>q;
for(int i = 1; i <= n; ++i){
for(int x : v[i]){
q.push({x, i});
}
int k = l;
while(!q.empty() && k--){
cout << q.front()[0] << ' ';
q.pop();
}
cout << 0 << endl;
}
}
