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