import math

while True:

    try:

        v = float(eval(input()))

    except:

        break

    print((math.floor(v ** 2 / 98 + 2)))
while 1:

 try:print((int(float(eval(input()))**2/98+2)))    

 except:break
import math

while True:
    try:
        v = float(eval(input()))
    except:
        break
    print((math.floor(v**2 / 98 + 2)))

while 1:
    try:
        print((int(float(eval(input())) ** 2 / 98 + 2)))
    except:
        break

-import math - -while True: +while 1: -        v = float(eval(input())) +        print((int(float(eval(input())) ** 2 / 98 + 2))) -    print((math.floor(v**2 / 98 + 2)))