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

int main() {
        unsigned long long int X;
        unsigned long long int M = 100;
        int i;
        scanf("%lld", &X);

        i = 1;
        while(1) {
                M = M * 1.01;
                if(M >= X) {
                        printf("%d\n", i);
                        return 0;
                }
                i++;
        }


        return 0;
}
