file_1 = open('1.txt', 'r').read().split('\n')
file_2 = open('2.txt', 'r').read().split('\n')

array = []
for email in file_1:
    if email.split(':')[0] not in file_2:
        array.append(email)

str = ""
for email in array:
    str += email
    str += '\n'

file_3 = open('3.txt', 'w')
file_3.write(str)