#include<bits/stdc++.h>
#define fo(i,d,c) for(int i=d;i<=c;i++)
#define fod(i,c,d) for(int i=c;i>=d;i--)
#define maxn 100010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout<<"\n";
//#define int long long
#define inf (int)1e18
#define pii pair<int,int>
#define vii vector<pii>
#define lb(x) x&-x
#define bit(i,j) ((i>>j)&1)
#define offbit(i,j) (i^(1<<j))
#define onbit(i,j) (i|(1<<j))
#define vi vector<int>
template <typename T1, typename T2> bool minimize(T1 &a, T2 b){if (a > b) {a = b; return true;} return false;}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b){if (a < b) {a = b; return true;} return false;}
using namespace std;
int cnt[maxn];
int n,d,m;
int sum[maxn];
vi ke[maxn];
int x,del,now;
bool check(int val)
{
fo(i,1,n) cnt[i] = sum[i];
now = 1;
fo(i,1,n)
{
if(now < i - d) return 0;
x = val;
while(x > 0)
{
del = min(cnt[now],x);
x -= del;
cnt[now] -= del;
if(cnt[now] == 0)
{
if(now < i) now++;
else break;
}
}
}
return 1;
}
main()
{
#define name "TASK"
if(fopen(name".inp","r"))
{
freopen(name".inp","r",stdin);
freopen(name".out","w",stdout);
}
ios_base::sync_with_stdio(false);cin.tie(NULL);
cin >> n >> d >> m;
fo(i,1,m)
{
cin >> x;
sum[x]++;
ke[x].pb(i);
}
int l = 1,r = m,ans,mid;
while(l <= r)
{
mid = (l + r) >> 1;
if(check(mid)) ans = mid,r = mid - 1;
else l = mid + 1;
}
cout << ans;en;
int pos = 0,now = 1;
fo(i,1,n)
{
x = ans;
while(x > 0)
{
del = min(sum[now],x);
x -= del;
sum[now] -= del;
for(int k = pos ; k < pos + del ; k++) cout << ke[now][k] << ' ';
pos += del;
if(sum[now] == 0)
{
if(now < i) now++,pos = 0;
else break;
}
}
cout << 0 << "\n";
}
}
