while True: try: num=float(input()) except: print() continue if num<2000: print("%.2f" % num) elif 2000 <= num < 3000: print("%.2f" % (num*0.8)) elif 3000 <= num < 4000: print("%.2f" % (num*0.7)) else: print("%.2f" % (num*0.6)) break