a=int(input()) a=float(a) if a<2000: print(a) if 2000<=a<3000: a=0.8*a a1='%.1f'%(a) print(a1) if 3000<=a<4000: a=0.7*a a1='%.1f'%(a) print(a1) if a>=4000: a=0.6*a a1='%.1f'%(a) print(a1)