def missingNumbers(arr, brr):
    brr.sort()
    arr.sort()
    biggest_val = brr[-1]
    arr_count_arr = [0] * (biggest_val + 1)
    brr_count_arr = [0]* (biggest_val + 1)
    
    result = []
    # print(brr_count_arr)
    
    for i in range(len(brr)):
        brr_count_arr[brr[i]] += 1
    
    for i in range(len(arr)):
        arr_count_arr[arr[i]] += 1
    
    for i in range(len(brr_count_arr)):
        if brr_count_arr[i] != arr_count_arr[i]:
            result.append(i)
    
    return result