Maximized Subset

For a multiset $A$ (a set whose elements may repeat), define the function $f(A)$ as follows: $f(A)$ is the largest integer $x$ such that every integer from $1$ to $x$ can be written as the sum of the elements of some sub-multiset of $A$, while $x + 1$ cannot be written as such a sum. (A sub-multiset is itself a multiset, so each element may be used only as many times as it appears in $A$.)

You are given a multiset $A$ with $n$ elements. Choose $k$ of its elements to form a sub-multiset $B$ so that $f(B)$ is as large as possible, and report that maximum value of $f(B)$.

The first line contains an integer $t$ ($1 \le t \le 100$), the number of test cases. Each test case consists of two lines. The first line contains two integers $n$ and $k$ ($1 \le k \le n \le 10^5$). The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 10^9$), separated by single spaces, the elements of $A$.

The sum of $n$ over all test cases does not exceed $10^6$.

For each test case, print on its own line a single integer: the maximum possible value of $f(B)$.