a = int(input()) if a >= 2000 and a < 3000: ans = a * 0.8 print("%.1f" % ans) elif a >= 3000 and a < 4000: ans = a * 0.7 print("%.1f" % ans) elif a >= 4000: ans = a * 0.6 print("%.1f" % ans) else: print("%.1f" % a)