"""
8 2 12
1 2 4 2 1 3 5 6 2 3 6 4
"""
from typing import NamedTuple
class Job(NamedTuple):
day: int
idx: int
days_cnt, max_delay, _ = map(int, input().split())
jobs = [Job(day, idx) for idx, day in enumerate(map(int, input().split()))]
jobs.sort()
max_repetition = 0
i = 0
while i < len(jobs):
cur_repetition = 1
while i + 1 < len(jobs) and jobs[i + 1].day == jobs[i].day:
cur_repetition += 1
i += 1
i += 1
max_repetition = max(max_repetition, cur_repetition)
l, r = 1, max_repetition + 1
def try_work(machines_cnt):
cur_path = []
job_i = 0
for day in range(1, days_cnt + 1):
if job_i == len(jobs):
cur_path.extend([[] for _ in range(days_cnt - day)])
break
cur_day_work = []
while len(cur_day_work) < machines_cnt and job_i < len(jobs) and jobs[job_i].day <= day:
if day - jobs[job_i].day > max_delay:
return False
cur_day_work.append(jobs[job_i].idx)
job_i += 1
cur_path.append(cur_day_work)
global path
path = cur_path
return True
path = []
while l < r:
mid = (l + r) // 2
if try_work(machines_cnt=mid):
r = mid
else:
l = mid + 1
print(l)
for work_done_in_day in path:
print(*work_done_in_day, 0)
