NO_OF_CHARS = 256
def str_to_list(string): 
	temp = [] 
	for x in string: 
		temp.append(x) 
	return temp 
def lst_to_string(List): 
	return ''.join(List) 
def get_char_count_array(string): 
	count = [0] * NO_OF_CHARS 
	for i in string: 
		count[ord(i)] += 1
	return count 
def remove_dirty_chars(string, second_string): 
	count = get_char_count_array(second_string) 
	ip_ind = 0
	res_ind = 0
	temp = '' 
	str_list = str_to_list(string) 
	while ip_ind != len(str_list): 
		temp = str_list[ip_ind] 
		if count[ord(temp)] == 0: 
			str_list[res_ind] = str_list[ip_ind] 
			res_ind += 1
		ip_ind+=1
	return lst_to_string(str_list[0:res_ind]) 