### Database Schema:
CREATE TABLE Airlines (
	FL_DATE	TEXT	NULL,
	OP_CARRIER_AIRLINE_ID	INTEGER	NULL,
	TAIL_NUM	TEXT	NULL,
	OP_CARRIER_FL_NUM	INTEGER	NULL,
	ORIGIN_AIRPORT_ID	INTEGER	NULL,
	ORIGIN_AIRPORT_SEQ_ID	INTEGER	NULL,
	ORIGIN_CITY_MARKET_ID	INTEGER	NULL,
	ORIGIN	TEXT	NULL,
	DEST_AIRPORT_ID	INTEGER	NULL,
	DEST_AIRPORT_SEQ_ID	INTEGER	NULL,
	DEST_CITY_MARKET_ID	INTEGER	NULL,
	DEST	TEXT	NULL,
	CRS_DEP_TIME	INTEGER	NULL,
	DEP_TIME	INTEGER	NULL,
	DEP_DELAY	INTEGER	NULL,
	DEP_DELAY_NEW	INTEGER	NULL,
	ARR_TIME	INTEGER	NULL,
	ARR_DELAY	INTEGER	NULL,
	ARR_DELAY_NEW	INTEGER	NULL,
	CANCELLED	INTEGER	NULL,
	CANCELLATION_CODE	TEXT	NULL,
	CRS_ELAPSED_TIME	INTEGER	NULL,
	ACTUAL_ELAPSED_TIME	INTEGER	NULL,
	CARRIER_DELAY	INTEGER	NULL,
	WEATHER_DELAY	INTEGER	NULL,
	NAS_DELAY	INTEGER	NULL,
	SECURITY_DELAY	INTEGER	NULL,
	LATE_AIRCRAFT_DELAY	INTEGER	NULL,
	foreign key (ORIGIN) references Airports (Code),
	foreign key (OP_CARRIER_AIRLINE_ID) references `Air Carriers` (Code),
	foreign key (DEST) references Airports (Code)
);

CREATE TABLE Airports (
	Code	TEXT	NULL	PRIMARY KEY,
	Description	TEXT	NULL
);

CREATE TABLE `Air Carriers` (
	Code	INTEGER	NULL	PRIMARY KEY,
	Description	TEXT	NULL
);

### User's Query:
How many flights from Charlotte Douglas International Airport to Austin - Bergstrom International Airport experienced serious reasons that cause flight cancellation?

### Extra Knowledge:
from refers to ORIGIN; Charlotte Douglas International Airport refers to Description = 'Charlotte, NC: Charlotte Douglas International'; to refers to DEST; Austin - Bergstrom International Airport refers to Description = 'Austin, TX: Austin - Bergstrom International'; serious reasons refers to CANCELLATION_CODE = 'A';
SELECT COUNT(*) FROM Airlines AS T1 INNER JOIN Airports AS T2 ON T1.ORIGIN = T2.Code WHERE T1.ORIGIN = 'CLT' AND T1.DEST = 'AUS' AND T2.Description = 'Charlotte, NC: Charlotte Douglas International' AND T1.CANCELLATION_CODE = 'A'