a = float(input()) b = 2000 c = 3000 d = 4000 if a >= b and a < c: a = a * 0.8 print("%.1f"%a) elif a >= c and a < d: a = a * 0.7 print("%.1f"%a) elif a >= d: a = a * 0.6 print("%.1f"%a) else: print("%.1f"%a)