#include <stdio.h>
#include <stdlib.h>

int main()
{
    long long int X;
    scanf("%lld",&X);
    long long int sum=100;
    int year=0;
    while(sum<X)
    {
        year++;
        sum=sum+sum*0.01;

    }
    printf("%d",year);

    return 0;
}
