QqP5e3xR

1GMAIL_DOMAIN = "gmail.com"
2
3def main(infile, outfile):
4    groups = {}
5    with open(infile, "r") as f:
6        cnt = int(f.readline())
7        for x in range(cnt):
8            addr = next(f).rstrip()
9            addr_lower = addr.lower()
10            login, domain = addr_lower.split("@")
11            if domain == GMAIL_DOMAIN:
12                if login.find(".") > 0:
13                    addr_lower = login.replace(".", "") + "@" + domain
14                if login.find("+") > 0:
15                    addr_lower = login[0:login.find("+")] + "@" + domain
16                #print(addr_lower)
17            if addr_lower not in groups:
18                groups[addr_lower] = list()
19            groups[addr_lower].append(addr)
20        #print(groups)
21
22    with open(outfile, "w") as f:
23        f.write("%s\n" % len(groups))
24        for k,v in groups.items():
25            f.write("%s %s\n" % (len(groups[k]), " ".join(groups[k])))
26
27
28if __name__ == "__main__":
29    main("input.txt", "output.txt")