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