print ("Welcome to my Quiz!")
existing = input("Are you an existing user?: ")
if existing.lower == "yes":
    print("Enter your credidentials")
username= input("Enter your Username: ")
password= input("Enter your Password: ")
file= open("data.txt", "r")
found=False
for line in file:
    account = line.split(",")
    if account[0] == username:
        password= existing[1]
        found=True
file.close()
if found==True:
    print("Welcome Back", username ,)
if found==False:
    print("Account not found")
else:
    existing.lower == "no"
    user= input("Enter your first name: ")
    year= input("Enter the year you are in: ")
    password= input("Enter your password: ")
    username=user[:2]+year
    writefile=open("data.txt","a")
    writefile.write(username + "," + password + "n")
    writefile.close()
    print("Your account has been created." "Your username is..", username , "..and your password is", password,)

print("Welcome to my Quiz!")

existing = input("Are you an existing user?: ")


if existing.lower() == "yes":
    print("Enter your Credidentials")

    username = input("Enter your Username: ")
    password = input("Enter your Password: ")

    with open("data.txt", "r") as raw_data:
        my_data = raw_data.read()

    re_data = my_data.split('n')

    for lines in re_data:

        split_line = lines.split(',')

        if username == split_line[0] and password == split_line[1]:
            print("Welcome Back " + username)

        else:
            print("Account not found")

else:

    user = input("Enter your first name: ")
    year = input("Enter the year you are in: ")
    password = input("Enter your password: ")
    username = user[:2]+year

    save_box = username + "," + password + "n"

    with open("data.txt", "a") as raw_data:
        raw_data.write(save_box)

    print("Your account has been created." "Your username is.." + username + "..and your password is" + password)


print("Goodbye, Have a Nice Day ...")

jack,6354734346534
edward,45645646754
jeje,874574574587

print ("Welcome to my Quiz!")
existing = input("Are you an existing user?: ")
if existing.lower()[0] == "y":
    print("Enter your credidentials")
    username= input("Enter your Username: ")
    password= input("Enter your Password: ")
    file= open("data.txt", "r")
    found=False
    for line in file:
        account = line.strip().split(",")
        if account[0] == username:
            password= account[1]
            found=True
    file.close()
    if found==True:
        print("Welcome Back", username )
    else:
        print("Account not found")
else:
    #print("Account not found")
    #existing.lower() == "no"
    user= input("Enter your first name: ")
    year= input("Enter the year you are in: ")
    password= input("Enter your password: ")
    username=user[:2]+year
    writefile=open("data.txt","a")
    writefile.write(username + "," + password + "n")
    writefile.close()
    print("Your account has been created." "Your username is..", username , "..and your password is", password,)