#include <stdio.h>
#include <limits.h>

int main(void) {
	unsigned long long int x = 0;
	unsigned long long int total = 100;
	int i;

	scanf("%lld", &x);

	for(i=1; ; i++) {
		total = total + total * 0.01;
		//printf("%lld\n", total);
		if(total>=x) {
			printf("%d", i);
			break;
		}
	}

	return 0;
}