text: import sqlite3 as sql
  
  db = sql.connect('dtb.db')
  cur = db.cursor()
  
  print("Welcome to our store. You can buy credits there.")
  
  print("""
  Prices:
  1 credit = 1 ¢
  
  """)
  
  cur.execute("SELECT credit FROM credits")
  
  beforeCredits = cur.fetchall()[0][0]
  
  request = int(input("How many credits you want to buy?"))
  
  cur.execute(f"UPDATE credits SET credit = {beforeCredits+request}")
  
  db.commit()
  db.close()