task	task time	tasks that must precede
A	30	--
B	16	A
C	19	A
D	20	--
E	20	B,C
F	18	D
G	12	E
H	45	F,G

The above tasks must be performed on an assembly line in the sequence and times specified. The workstation cycle time is 51 seconds. Using the longest task time to balance the assembly line, the first workstation include________ , the second workstation include _______ , the third workstation include________ , and the fourth workstation include__________ . (For each blank write tasks in alphabetical order without space or comma. For example, if workstation 1 includes task A, task C and task E, write them as ACE, not A,C,E, A C E or CAE.)