BR password challenge (using scanf)

BR_password_challenge_scanf.c

int main(void) {
	int lower_length = 0,
	    upper_length = 0,
	    digit_length = 0,
	    length = 0;
	    
    puts("Please enter a password and I'll judge its security...");
    
#   define LOWER_FMT "%*[qwertyuiopasdfghjklzxcvbnm]%n"
#   define UPPER_FMT "%*[QWERTYUIOPASDFGHJKLZXCVBNM]%n"
#   define DIGIT_FMT "%*[1234567890]%n"
    scanf(LOWER_FMT, &lower_length);
    scanf(UPPER_FMT, &upper_length);
    scanf(DIGIT_FMT, &digit_length);

    if (scanf(LOWER_FMT, &length) == 0) { lower_length += length; length = 0; }
    if (scanf(UPPER_FMT, &length) == 0) { upper_length += length; length = 0; }
    if (scanf(DIGIT_FMT, &length) == 0) { digit_length += length; length = 0; }
    if (scanf("%*s%n",   &length) != 0) { length = 0; }
	
    length += lower_length + upper_length + digit_length;
	
#   define AT_LEAST "Your password must contain at least "
    puts(lower_length == 0 ? AT_LEAST "one lower alpha character"
       : upper_length == 0 ? AT_LEAST "one upper alpha character"
       : digit_length == 0 ? AT_LEAST "one decimal digit character"
       : length < 8        ? AT_LEAST "eight characters"
                           : "Your password seems secure to me!");

	return 0;
}