Handling Multiple FULL OUTER JOIN in sql

SELECT A.column2 , B.column2 , C.column2 FROM ( 
 (SELECT month, column2 FROM table1) 
A 
 FULL OUTER JOIN 
 (SELECT month, column2 FROM table2) 
B on A.month= B.month 
 FULL OUTER JOIN 
 (SELECT month, column2 FROM table3) 
C on ISNULL(A.month, B.month) = C.month )