// Source: https://usaco.guide/general/io
#include <bits/stdc++.h>
using namespace std;
long long n, d, m;
vector <pair<long long, long long>> a;
bool f(long long x){
long long g;
multiset<long long> b;
for (long long i = 0; i < x; i++) b.insert(0);
for (long long i = 0; i < m; i++){
g=*b.begin();
if(g-a[i].first>d) return 0;
b.erase(b.find(g));
b.insert(max(g, a[i].first)+1);
}
return 1;
}
int main() {
long long x=0, y=1;
cin >> n >> d >> m;
vector<set<long long>> c(n+1);
a.resize(m);
for (long long i = 0; i < m; i++) {cin >> a[i].first; a[i].second=i+1;}
sort(a.begin(), a.end());
while(!f(y)) y*=2;
for (long long i = y/2; i>=1; i/=2){
while(i+x<=y&&(!f(i+x))) x+=i;
}
cout << ++x;
long long g;
multiset<long long> b;
for (long long i = 0; i < x; i++) b.insert(0);
for (long long i = 0; i < m; i++){
g=*b.begin();
b.erase(b.find(g));
b.insert(max(g, a[i].first)+1);
c[max(g, a[i].first)].insert(a[i].second);
}
cout << endl;
for (long long i = 1; i <= n; i++){
for (auto j:c[i]){
cout << j << ' ';
}
cout << 0 << endl;
}
}
