instruction: what is the earliest flight from BOSTON to ATLANTA
response: SELECT DISTINCT flight.flight_id FROM airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, city AS CITY_0, city AS CITY_1, flight WHERE (CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'BOSTON' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'ATLANTA' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND flight.departure_time = (SELECT MIN(FLIGHTalias1.departure_time) FROM airport_service AS AIRPORT_SERVICEalias2, airport_service AS AIRPORT_SERVICEalias3, city AS CITYalias2, city AS CITYalias3, flight AS FLIGHTalias1 WHERE CITYalias2.city_code = AIRPORT_SERVICEalias2.city_code AND CITYalias2.city_name = 'BOSTON' AND CITYalias3.city_code = AIRPORT_SERVICEalias3.city_code AND CITYalias3.city_name = 'ATLANTA' AND FLIGHTalias1.from_airport = AIRPORT_SERVICEalias2.airport_code AND FLIGHTalias1.to_airport = AIRPORT_SERVICEalias3.airport_code)