output_description: Print the answer.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N
attempt:     import numpy as np
      n,m=map(int, input().split())
       
      if n>=m/2:
        print("m//2")
      else:
        m_aft = m -2*n
        m_fin = m_aft//4
        print(n+m_fin)
problem_description: Statement
  
  Snuke has a favorite restaurant.
  
  The price of any meal served at the restaurant is 800 yen (the currency of
  Japan), and each time a customer orders 15 meals, the restaurant pays 200 yen
  back to the customer.
  
  So far, Snuke has ordered N meals at the restaurant. Let the amount of money
  Snuke has paid to the restaurant be x yen, and let the amount of money the
  restaurant has paid back to Snuke be y yen. Find x-y.
samples: [{"input": "20", "output": "15800\n    \n\nSo far, Snuke has paid 16000 yen, and the restaurant has paid back 200 yen.\nThus, the answer is 15800.\n\n* * *"}, {"input": "60", "output": "47200\n    \n\nSnuke has paid 48000 yen for 60 meals, and the restaurant has paid back 800\nyen."}]