from sys import exit



def main():

    X = int(eval(input()))

    deposit = 100



    i = 0

    while True:

        deposit = int(deposit * 1.01)

        i += 1



        if deposit >= X:

            print(i)

            exit()



if __name__ == '__main__':

    main()
# from sys import exit



def main():

    x = int(eval(input()))

    d = 100

    ans = 0

    

    while d < x:

        d = int(d*1.01)

        ans += 1

    print(ans)



if __name__ == '__main__':

    main()
from sys import exit


def main():
    X = int(eval(input()))
    deposit = 100
    i = 0
    while True:
        deposit = int(deposit * 1.01)
        i += 1
        if deposit >= X:
            print(i)
            exit()


if __name__ == "__main__":
    main()

# from sys import exit
def main():
    x = int(eval(input()))
    d = 100
    ans = 0
    while d < x:
        d = int(d * 1.01)
        ans += 1
    print(ans)


if __name__ == "__main__":
    main()

-from sys import exit - - +# from sys import exit -    X = int(eval(input())) -    deposit = 100 -    i = 0 -    while True: -        deposit = int(deposit * 1.01) -        i += 1 -        if deposit >= X: -            print(i) -            exit() +    x = int(eval(input())) +    d = 100 +    ans = 0 +    while d < x: +        d = int(d * 1.01) +        ans += 1 +    print(ans)