#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <stack>
#include <map>
#include <queue>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cstring>
#include <cmath>
#include <functional>
#include <cassert>
#include <iomanip>
#include <numeric>
//#include <bit>
#define INF 2e9
#define LL_INF 9223372036854775806
#define ff first
#define ss second
#define mod 1000000007
#define ll long long
#define PB push_back
#define MP make_pair
#define MT make_tuple
#define EB emplace_back
#define PoB pop_back
#define LOG log2
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define fch(t, v) for (auto t : v)
#define sz(x) int(x.size())
#define rsz resize
#define gp(x) vector<vector<x>>
#define btree vector<pii>
#define vc(x) vector<x>
#define vll vector<ll>
#define Max(a, b, c) max(max(a,b),c)
#define fMax(a, b, c, d) max(Max(a, b, c), d)
#define Min(a, b, c) min(min(a,b),c)
#define Mid(a, b, c) max(min(a, b), min(max(a, b), c))
#define st(a) set<a>
#define gr(x) greater<x>
#define gi greater<int>
#define all(x) (x).begin(),(x).end()
#define tri(x) tuple<x,x,x>
#define quad(x) tuple<x,x,x,x>
#define eps 1e-9
using namespace std;
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
void setIO(const string& str) {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
if (str.empty()) return;
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
int N, D, M;
vi req;
vc(pii) idx;
int main() {
setIO("");
cin >> N >> D >> M;
req.rsz(M);
for (int i = 0; i < M; ++i) {
cin >> req[i];
idx.PB({req[i], i});
}
sort(all(req)), sort(all(idx));
int l = 1, r = M;
auto check = [&](int x) ->bool {
int day = 1, cnt = 0;
for (int i = 0; i < M; ++i) {
cnt++;
if (req[i] > day) day = req[i], cnt = 0;
if (day-req[i] > D) return false;
if (cnt == x) cnt = 0, day++;
}
return true;
};
while (l <= r) {
int mid = (l + r)/2;
if (check(mid)) {
r = mid-1;
} else {
l = mid+1;
}
}
cout << r+1 << endl;
int i = 0;
int d = 0;
while (i < M) {
for (int j = 1; j <= r+1; ++j) {
cout << idx[i++].ss+1 << " ";
if (i == M) break;
}
cout << 0 << endl;
d++;
}
for (int j = d+1; j <= N; ++j) {
cout << 0 << endl;
}
}
