a=int(input()) y=0 z=0 if a>=2000: x=(a-2000)*0.8 n=2000+x if a>=3000: y=(a-3000)*0.7 n=2000+800+y if a>=4000: z=(a-4000)*0.6 n=2000+800+700+z print(n) else: print(n) else: print(n) else: print(a)