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