find the minimum number of sets

Let's explain my question with example I have some integer sets for example

set number 1 :2,3

set number 2 :2,5

set number 3 :4,5

set number 4 :4

set number 5 :5

And I have sample set with 4 element 2 3 4 5 so now I want to find minimum number of set to built my sample set in this case I can use set number 1 and 3 because set number one has 2,3 and set number 2 has 4,5 together they are as same as my sample test we can use set number 1,4,5 but that isn't a sufficient answer so how can find this minimum number of set??

Isn't it a kind of knapsack problem?