#include<stdio.h>
int main() {
    long long x;
    scanf("%lld", &x);
    long long year = 0;
    long long amount = 100;
    while (amount < x)
    {
        amount = amount + amount / 100;
        year = year + 1;
    }
    printf("%lld\n", year);



    return 0;
}