```py  
from flask import Flask, request, render_template, render_template_string,
redirect  
import subprocess  
import urllib  
flag = open('flag.txt').read()  
app = Flask(__name__)  
@app.route('/')  
def main():  
return redirect('/login')

@app.route('/login',methods=['GET','POST'])  
def login():  
if request.method == 'GET':  
return render_template('login.html')  
elif request.method == 'POST':  
if len(request.values["username"]) >= 40:  
return render_template_string("Username is too long!")  
elif len(request.values["username"].upper()) <= 50:  
return render_template_string("Username is too short!")  
else:  
return flag  
if __name__ == '__main__':  
app.run(host='0.0.0.0', port=8000)  
```

My [teammate](https://github.com/Fundaystrike) found that `ß` when uppercase
is `SS`. So just submit with 25 of them to pass the checks.
`ßßßßßßßßßßßßßßßßßßßßßßßßßßß`

Flag: `n00bz{1mp0551bl3_c0nd1t10n5_m0r3_l1k3_p0551bl3_c0nd1t10ns}`

Original writeup (https://jp-ch.gq/web/n00bzCTF-2023.html#conditions).