#include <bits/stdc++.h>
using namespace std;
#define int long long
#define N 1000005
#define ff first
#define ss second
const int inf = 1e18;
int n, m, t;
pair <int,int> a[N];
int32_t main() {
ios::sync_with_stdio(0);cin.tie(0);
cin >> n >> m >> t;
for(int i = 1; i <= t; i++) {
cin >> a[i].ff;
a[i].ss = i;
}
sort(a + 1, a + t + 1);
int l = 1, r = 1e5, jog = 0;
while(l <= r) {
int mid = (l + r) / 2, ind = 1;
for(int i = 1; i <= n; i++) {
int op = mid;
while(ind <= t && op > 0 && i >= a[ind].ff && a[ind].ff + m >= i) {
op--;
ind++;
}
}
if(ind <= t) l = mid + 1;
else r = mid - 1, jog = mid;
}
cout << jog << endl;
int ind = 1;
for(int i = 1; i <= n; i++) {
int op = jog;
while(op > 0 && ind <= t && i >= a[ind].ff && a[ind].ff + m >= i) {
cout << a[ind].ss << " ";
ind++;
op--;
}
cout <<false << '\n';
}
return 0;
}
