Excel 2007 : adding values with unique identifiers

Hi guys,

I'm trying to do the following. I can't seem to describe it in plain English, that's why I can't find a solution with Google. So here goes:

Suppose you have the following data:
1 105,45
1 34,23
1 123,40
1 90,50
1 234,04
1 12,40
2 123,00
3 87,45
3 9,65
3 32,60
4 7,40
4 0,65
5 65,24
6 456,43
7 234,06
8 24,68
8 65,23
8 12,40

I want to add the values of the second column together for each unique identifier, so the result would be:
1 600,02
2 123,00
3 129,70
4 8,05
5 65,24
6 456,43
7 234,06
8 102,31

Any ideas how I can do this for large data sets?

EDIT: for clarity, first numbers of each row are in one column, the rest of the numbers in each row in the second column.