#include <stdio.h>
#include <inttypes.h>

int main(void) {
	uint64_t horieyui = 100;
	uint64_t X;
	uint64_t tamurayukari = 0;
	if (scanf("%" SCNu64, &X) != 1) return 1;
	while (horieyui < X) {
		horieyui += horieyui / 100;
		tamurayukari++;
	}
	printf("%" PRIu64 "\n", tamurayukari);
	return 0;
}
