login = input("To sign in type 1. To register a new account type 2: ")
if login == "1":
    log_username = True
    while log_username == True:
        user = input("Username: ")
        user_password = input("Password: ")
        saved_users = open(user+".csv","r")
        for line1 in saved_users:
            line1.split(",")
            for line2 in saved_users:
                line2.split(",")
                if user == saved_users:
                    if user_password == saved_users:
                            print("Login successful...")
                    else:
                        print("Incorrect password")
                        log_username == False
                else:
                    print("Incorrect username, please try again.")
                    log_username == False