text: #!/bin/python3
  
  import math
  import os
  import random
  import re
  import sys
  
  #
  # Complete the 'getTotalX' function below.
  #
  # The function is expected to return an INTEGER.
  # The function accepts following parameters:
  #  1. INTEGER_ARRAY a
  #  2. INTEGER_ARRAY b
  #
  
  
  
  def getTotalX(a, b):
      # Write your code here
      count = 0
      maximumA = max(a)
      maximumB = max(b)
      minimumA = min(a)
      minimumB = min(b)
      for i in range(minimumA,maximumB+1):
          # print(i)
          flag = 0
          for j in a:
              if i%j != 0:
                  flag = 1
                  break
          for k in b:
              if k%i != 0:
                  flag = 1
                  break
          if flag == 0:
              print(i)
              count += 1
      return count
                  
  
  if __name__ == '__main__':
      fptr = open(os.environ['OUTPUT_PATH'], 'w')
  
      first_multiple_input = input().rstrip().split()
  
      n = int(first_multiple_input[0])
  
      m = int(first_multiple_input[1])
  
      arr = list(map(int, input().rstrip().split()))
  
      brr = list(map(int, input().rstrip().split()))
  
      total = getTotalX(arr, brr)
  
      fptr.write(str(total) + '\n')
  
      fptr.close()
  