Previous four months First Day

Hi All,

I am having a requirement, to show Previous four months first day.

I Having few objects.

Year, Calendar Day, Net Value(Measure)

(Year=2014,2015,2016)

Calendar Day = 1/1/2014,1/2/2014.......2/3/2016)

Net Value= 256875

I need to Display, Previous four months first day(Each month in different blocks)

Ex:

I need to create these in webi report itself.