You are now a sqlite data analyst, and you are given a database schema as follows:

    【Schema】
    【DB_ID】 financial
【Schema】
# Table: client
[
(client_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(gender:TEXT, Examples: [F, M]),
(birth_date:DATE, Examples: [1970-12-13]),
(district_id:INTEGER, Examples: [18, 1, 5])
]
# Table: card
[
(card_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(disp_id:INTEGER, Examples: [9, 19, 41]),
(type:TEXT, Examples: [gold, classic, junior]),
(issued:DATE, Examples: [1998-10-16])
]
# Table: disp
[
(disp_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(client_id:INTEGER, Examples: [1, 2, 3]),
(account_id:INTEGER, Examples: [1, 2, 3]),
(type:TEXT, Examples: [OWNER, DISPONENT])
]
# Table: account
[
(account_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(district_id:INTEGER, Examples: [18, 1, 5]),
(frequency:TEXT, Examples: [POPLATEK MESICNE, POPLATEK TYDNE, POPLATEK PO OBRATU]),
(date:DATE, Examples: [1995-03-24])
]
# Table: district
[
(district_id:INTEGER, Primary Key, Examples: [1, 2, 3]),
(A2:TEXT, Examples: [Hl.m. Praha, Benesov, Beroun]),
(A3:TEXT, Examples: [Prague, central Bohemia, south Bohemia]),
(A4:TEXT, Examples: [1204953, 88884, 75232]),
(A5:TEXT, Examples: [0, 80, 55]),
(A6:TEXT, Examples: [0, 26, 29]),
(A7:TEXT, Examples: [0, 6, 4]),
(A8:INTEGER, Examples: [1, 2, 3]),
(A9:INTEGER, Examples: [1, 5, 6]),
(A10:REAL, Examples: [100.0, 46.7, 41.7]),
(A11:INTEGER, Examples: [12541, 8507, 8980]),
(A12:REAL, Examples: [0.2, 1.6, 1.9]),
(A13:REAL, Examples: [0.43, 1.85, 2.21]),
(A14:INTEGER, Examples: [167, 132, 111]),
(A15:INTEGER, Examples: [85677, 2159, 2824]),
(A16:INTEGER, Examples: [99107, 2674, 2813])
]
# Table: order
[
(order_id:INTEGER, Primary Key, Examples: [29401, 29402, 29403]),
(account_id:INTEGER, Examples: [1, 2, 3]),
(bank_to:TEXT, Examples: [YZ, ST, QR]),
(account_to:INTEGER, Examples: [87144583, 89597016, 13943797]),
(amount:REAL, Examples: [2452.0, 3372.7, 7266.0]),
(k_symbol:TEXT, Examples: [SIPO, UVER, POJISTNE])
]
# Table: loan
[
(loan_id:INTEGER, Primary Key, Examples: [4959, 4961, 4962]),
(account_id:INTEGER, Examples: [2, 19, 25]),
(date:DATE, Examples: [1994-01-05]),
(amount:INTEGER, Examples: [80952, 30276, 318480]),
(duration:INTEGER, Examples: [24, 12, 60]),
(payments:REAL, Examples: [3373.0, 2523.0, 5308.0]),
(status:TEXT, Examples: [A, B, D])
]
# Table: trans
[
(trans_id:INTEGER, Primary Key, Examples: [1, 5, 6]),
(account_id:INTEGER, Examples: [1, 2, 3]),
(date:DATE, Examples: [1995-03-24]),
(type:TEXT, Examples: [PRIJEM, VYDAJ, VYBER]),
(operation:TEXT, Examples: [VKLAD, PREVOD Z UCTU, PREVOD NA UCET]),
(amount:INTEGER, Examples: [1000, 3679, 2452]),
(balance:INTEGER, Examples: [1000, 4679, 20977]),
(k_symbol:TEXT, Examples: [SIPO, SLUZBY, UVER]),
(bank:TEXT, Examples: [AB, YZ, ST]),
(account:INTEGER, Examples: [41403269, 87144583, 66487163])
]
【Foreign keys】
client.district_id=district.district_id
card.disp_id=disp.disp_id
disp.account_id=account.account_id
disp.client_id=client.client_id
account.district_id=district.district_id
order.account_id=account.account_id
loan.account_id=account.account_id
trans.account_id=account.account_id

    【Question】
    How many clients who were born in 1920 stay in east Bohemia? East Bohemia appears in the column A3, which refers to the region.

    【Evidence】
    East Bohemia appears in the column A3, which refers to the region.

    Please read and understand the database schema carefully, and generate an executable SQL based on the user's question and evidence. 

SQL: SELECT COUNT(T1.client_id) FROM client AS T1 INNER JOIN district AS T2 ON T1.district_id = T2.district_id WHERE STRFTIME('%Y', T1.birth_date) = '1920' AND T2.A3 = 'east Bohemia'