Available are: 1 4 3 1
Only P0 is satisfying , Now available is 1 4 5 2
Only P3 is satisfying, Now available is 1 11 9 4
Now either P2 or P4 any can go
if P2 goes: then P1 and P4 may follow any order : 2 sequences.
if P4 goes: then P1 and P2 may follow any order : 2 sequences.
Total 4 Sequences.