fill multiple columns having missing values with known non-missing values by id

[CHL0320]

Hi, How do I carry the non-missing up or down within the same ID? The final output is one ID per line. 

Before: 

ID	A	B	C	D	E	F
1	20	11	.	1	.	40
1	20	11	.	1	36	.
1	20	11	45	1	.	.
2	75	18	76	2	.	.
2	75	18	.	2	.	.
2	75	18	76	2	83	.
3	23	3	.	3	.	.
3	23	3	.	3	57	73
3	23	3	61	3	.	.

After:

ID	A	B	C	D	E	F
1	20	11	45	1	36	40
2	75	18	76	2	83	.
3	23	3	61	3	57	73

Thank you

[novinosrin · Accepted solution]

data have;
input ID	A	B	C	D	E	F;
cards;
1	20	11	.	1	.	40
1	20	11	.	1	36	.
1	20	11	45	1	.	.
2	75	18	76	2	.	.
2	75	18	.	2	.	.
2	75	18	76	2	83	.
3	23	3	.	3	.	.
3	23	3	.	3	57	73
3	23	3	61	3	.	.
;

data want;
update have(obs=0) have;
by id;

run;