def resolve():

	s = 100

	x = int(eval(input()))

	step = 0

	while s < x:

		step += 1

		s += s // 100

	print(step)

resolve()
import math

def resolve():

	x = int(eval(input()))

	v = 100

	y = 0

	while True:

		y += 1

		v += math.floor(v*0.01)

		if v >= x:

			print(y)

			return

resolve()
def resolve():
    s = 100
    x = int(eval(input()))
    step = 0
    while s < x:
        step += 1
        s += s // 100
    print(step)


resolve()

import math


def resolve():
    x = int(eval(input()))
    v = 100
    y = 0
    while True:
        y += 1
        v += math.floor(v * 0.01)
        if v >= x:
            print(y)
            return


resolve()

+import math + + -    s = 100 -    step = 0 -    while s < x: -        step += 1 -        s += s // 100 -    print(step) +    v = 100 +    y = 0 +    while True: +        y += 1 +        v += math.floor(v * 0.01) +        if v >= x: +            print(y) +            return