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

int main()
{
    unsigned long long int x, deposit = 100;
    scanf("%llu", &x);

    int year = 1;

    while(1)
    {
        deposit += (.01*deposit);

        if(deposit >= x)
            break;

        year++;
    }

    printf("%d\n", year);

    return 0;
}
