from collections import Counter
from math import sqrt


def is_prime(n):
    if n == 2:
        return True
    elif n < 2 or n % 2 == 0:
        return False

    k = 3
    while k <= int(sqrt(n)):
        if n % k == 0:
            return False
        k += 2
    return True


def fun(A, B):
    counter = Counter()
    for b in B:
        counter[b] += 1
    C = []
    for a in A:
        # if a was not in B counter[a]=0
        if not is_prime(counter[a]):
            C.append(a)
    return C