Here's my problem today:

Date Sender Date Reciever Recieved

02.04 344 02.04 341 8390
03.04 344 03.04 341 6690
02.05 344 04.05 341 5960
06.05 344 06.05 341 10450

What I want to do is create formulas that sums up recieved pr. month using
sumif. Say I've got input values in sheet1 and i want monthly sums in sheet2
that generates automaticly. How do I solve this without each month having to
sum up manually?

(Sorry for my poor english)