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