Combinations and the number of calls

$C(n, k)$ is the number of ways to choose $k$ items out of $n$. It is computed recursively by Pascal's rule:

C(n, k):
    if k == 0 or k == n: return 1
    return C(n - 1, k - 1) + C(n - 1, k)

Find $C(n, k)$ and how many times in total this function is called (the first call counts too).

A single line with $n$ and $k$ ($0 \le k \le n \le 20$).

A single line with two numbers: $C(n, k)$ and the number of calls.

$C(4, 2)$: C(4,2) → C(3,1), C(3,2); C(3,1) → C(2,0), C(2,1); C(2,1) → C(1,0), C(1,1); C(3,2) gives the same $5$ calls. In total $1 + 5 + 5 = 11$ calls, and $C(4, 2) = 6$. Count with a global counter.