Showing all combinations of a set of numbers

I have 20 numbers for which I want to find all of the combinations of 8 of these numbers that sum to 26 is this possible to do?

Edit 1:
Below in the first column is the 20 numbers that I'm talking about.

In the second column are the numbers that are associated to the numbers in the first column.

In a nutshell my problem is that I want to find the largest sum of 8 of the numbers in the second column, however, the total for the numbers associated with them (in the first column) cannot exceed 26.

6 163
1 55
1 46
6 142
2 55
1 78
2 99
3 83
1 39
1 41
2 32
4 83
4 92
4 123
2 55
2 53
6 100
2 62
2 52
2 107