input: 
  from flask import Flask, render_template, request
  
  app = Flask(__name__)
  
  @app.route('/', methods=['GET', 'POST'])
  def home():
      """
      A web application that takes user input and generates an HTML page with the input.
      
      Example:
      Input (through the web form): "Hello World"
      Output (on the result page): "Hello World"
      """
      if request.method == 'POST':
          input_text = request.form.get('input_text')
          return render_template('result.html', input_text=input_text)
      return render_template('index.html')
  
  if __name__ == '__main__':
      app.run(debug=True)
  
output:     
      if request.method == 'POST':
          input_text = request.form.get('input_text')
          return render_template('result.html', input_text=input_text)
      return render_template('index.html')
  