import math
import os
import random
import re
import sys
from functools import reduce

def lcm(x, y):
    return x * y // math.gcd(x, y)

def getTotalX(a, b):
    l = reduce(lcm, a)
    g = reduce(math.gcd, b)
    count = 0
    for i in range(l, g + 1, l):
        if g % i == 0:
            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()