minute calculation

[Johnson5]

I have the following columns and I'm trying to calculate the difference in minutes between rows?
So in the second row, the difference should be: 23:54-12:26 = 688 minutes
Third row should be: 9:02-23:54 = 548 minutes

Day	Hours24	Minutes	Difference Minutes
1	12	26
1	23	54
2	9	2
2	11	32

<colgroup><col width="64" span="4" style="width:48pt"> </colgroup><tbody>
</tbody>

I can probably get the answer using a few IF functions but the equation is quite long, I was wondering if there are any shorter ways?

Thanks

 

[Aladin Akyurek]

D2, copied down:

=IF($A2<>$A1,(($B3&":"&$C3)-($B2&":"&$C2))*1440,"")

I suppose the difference on Day 2 is 150, not 548, minutes.