X=int(eval(input()))

n=100

for i in range(10**10):

    if n>=X:

        print(i)

        exit()

    n+=n//100
X=int(eval(input()))

n=100

for i in range(10000):

    if n>=X:

        print(i)

        exit()

    n+=n//100
X = int(eval(input()))
n = 100
for i in range(10**10):
    if n >= X:
        print(i)
        exit()
    n += n // 100

X = int(eval(input()))
n = 100
for i in range(10000):
    if n >= X:
        print(i)
        exit()
    n += n // 100

-for i in range(10**10): +for i in range(10000):