The degree of unsaturation can be calculated as
#C + 1 - (#H + #halogens)/2 + #N/2 . .in you case that is
5 + 1 - (9/2) + 1/2 = 2
There are 2 degrees of unsaturation . . .two double bonds or one triple bond. A closed ring also counts as one degree of unsaturation.
HOPE THIS HELPED :)
