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