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