output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      A_1 A_2 \dots A_N
attempt: n, k = map(int, input().split(" "))
  num = list(map(int, input().split(" "))).sort()
  p_num = [i for i in num if i > 0]
  zero_num = [i for i in num if i == 0]
  n_num = [i for i in num if i < 0]
  positive = len(p_num) * (len(p_num) - 1) + len(n_num) * (len(n_num) - 1)
  zero = len(zero_num) * (len(p_num) + len(n_num))
  negative = len(n_num) * len(p_num)
  if k - negative <= 0:
      multiplication_list = [i * j for i in n_num for j in n_num]
      multiplication_list.sort()
      print(multiplication_list[k - 1])
  elif k - n_num - zero <= 0:
      print(0)
  else:
      idx = k - n_num - zero
      multiplication_list_1 = [
          p_num[i] * p_num[j] for i in range(len(p_num)) for j in range(i + 1, len(p_num))
      ]
      multiplication_list_2 = multiplication_list = [
          n_num[i] * n_num[j] for i in range(len(n_num)) for j in range(i + 1, len(n_num))
      ]
      multiplication_list = multiplication_list_1 + multiplication_list_2
      multiplication_list.sort()
      print(multiplication_list[idx])
  
problem_description: Statement
  
  We have N integers A_1, A_2, ..., A_N.
  
  There are \frac{N(N-1)}{2} ways to choose two of them and form a pair. If we
  compute the product of each of those pairs and sort the results in ascending
  order, what will be the K-th number in that list?
samples: [{"input": "4 3\n    3 3 -4 -2", "output": "-6\n    \n\nThere are six ways to form a pair. The products of those pairs are 9, -12, -6,\n-12, -6, 8.\n\nSorting those numbers in ascending order, we have -12, -12, -6, -6, 8, 9. The\nthird number in this list is -6.\n\n* * *"}, {"input": "10 40\n    5 4 3 2 -1 0 0 0 0 0", "output": "6\n    \n\n* * *"}, {"input": "30 413\n    -170202098 -268409015 537203564 983211703 21608710 -443999067 -937727165 -97596546 -372334013 398994917 -972141167 798607104 -949068442 -959948616 37909651 0 886627544 -20098238 0 -948955241 0 -214720580 277222296 -18897162 834475626 0 -425610555 110117526 663621752 0", "output": "448283280358331064"}]