#include <stdio.h>

int main(void) {
	unsigned long long int X, ret;
	unsigned short i;
	scanf("%llu%*c", &X);
	ret = 100;
	for (i = 0; ret < X; i++) {
		ret += ret * 0.01;
	}
	printf("%hu\n", i);
	return 0;
}
