How do i add rows in a table SQLite

Question

I have this table in SQLite3 and I don't know how to add the values of two rows from the same column...

question: Print the sum of Nr_student from Bucuresti and Timisoara. My idea looks like this: SELECT Nr_student(there is the problem Idk what to do in this point) AS Nr_students_TIMISOARA_BUCURESTI FROM Universities WHERE County ='Bucuresti' AND County='Timisoara' ;

CREATE TABLE Universities (Cod_university Number(4), Name VARCHAR2(20), County VARCHAR2(15), Nr_student NUMBER(5), Nr_bursieri NUMBER(5), Nr_specialty NUMBER(2))

INSERT INTO Universities VALUES (100, 'UBB', 'Cluj', 65310, 589, 20) INSERT INTO Universities VALUES (153, 'UPT', 'Timisoara', 59968, 945, 12) INSERT INTO Universities VALUES (106, 'UVT', 'Timisoara', 48962, 1000, 9) INSERT INTO Universities VALUES (231, 'UPET', 'Petrosani', 643, 30, 11) INSERT INTO Universities VALUES (51, 'UAIC', 'Iasi', 8684, 600, 26) INSERT INTO Universities VALUES (51, 'UNIBUC', 'Bucuresti', 812, 624, 32)