Amazon OA: Channels & Packets

#python 3.7.1
from math import floor, ceil
n = int(input())
m = int(input())
packets = list(map(int, input().split()))
packets.sort(reverse=True)
quality = 0
p = 0
a = 0
for i in range(m-1):
  quality += packets[i]
  if packets[i] == p:
    a += 1
  else:
    p = packets[i]
    a = 1
b = 0
c = 0
d = 1
for i in range(m-1, n):
  if packets[i] == p:
    b += 1
  elif packets[i] == p-1:
    c += 1
  d += 1
d = d/2.0
shift = 2*(d-b)
if a >= shift-1 and c >= shift:
  quality += p
else:
  quality += ceil((packets[m-2+floor(d)]+packets[m-2+ceil(d)])/2.0)
print(quality)

'''
8
4
2 2 2 2 3 3 3 3

8
4
2 2 1 2 3 3 3 3
'''