from flask import Flask, request

app = Flask(__name__)

@app.route('/')
def a():
    return '''
    <form action="/l">
    <div>Username: <input name="u"></div><br>
    <div>Password: <input name="p" type="password"></div><br>
    <div><input type="submit" value="Login"></div>
    </form>
    '''

@app.route('/l')
def b():
    if request.args.get('u') == "admin" and request.args.get('p') == "1234":
        return "Login Successful"
    else:
        return "Invalid"

if __name__ == "__main__":
    app.run()