Formula that counts everything except duplicates...

Hi,

New here so forgive me.

I have a uni problem, I would like to count the number of trucks used each day for each shift(day & night), that operated under a specific digger.
That part is easy.
The issue is: if one truck was used by two different people in one shift, the imported data will say it operated twice. I would like to do a count which ignores duplicate truck ID's for each shift, so that each truck is only counted once per shift if used at all.

For some reason photos wont upload, so:

Summary Data Tab: (Counting Duplicates)

______C______D__________E_________F__G__H__I

_____Date___Shift___Total # Trucks__Actual # Trucks

__________________________________A__B__C__D

04__2/1/14____D_________10________2__4__0__4
05__2/1/14____N__________3________1__0__0__2
06__3/1/14____D__________0________0__0__0__0
07__3/1/14____N_________11________3__3__3__2


Import Data Tab:

______F______G_______H__________I____________J____________K

____Date____Shift___Truck I.D.__Digger I.D____Workhours____Truck Type

04__2/1/14____D_____21335______22225_________6 ___________D
05__2/1/14____D_____21334______22225________4.8___________D
06__2/1/14____D_____21302______22225_________7 ___________D
07__2/1/14____D_____21334______22225________3.9___________D
08__2/1/14____D_____21335______22225_________2 ___________A
09__2/1/14____D_____33748______22225_________1 ___________A
10__2/1/14____D_____21381______22225________3.8___________C
11__2/1/14____D_____21380______22225_________3 ___________C
12__2/1/14____D_____21374______22225_________2 ___________C
13__2/1/14____D_____21570______22225________2.4___________C




My Summary data tab holds the formulas I've created (based on the data that is imported into the 'Import data tab'), as you can see it is counting 10 trucks used for 2/1/14 day shift.
When in fact 8 trucks were used that day on day shift, of which two trucks were used by two different employees.


Please help, I've fiddled with this for far too long...


Cheers

Thanks for the prompt reply guys!!

big thanks to CANAPONE I should deffinitely be able to get it from there!!