can anyone help me out with this C# code its failing fro one testcase:

public static int beautifulPairs(List A, List B) { HashSet setB = new HashSet(B); int bPairs = 0;

foreach (int i in A)
{
    if (setB.Contains(i))
    {
        bPairs++;
        setB.Remove(i); // Ensures pairwise disjoint condition
    }
}

// If all elements are matched, changing any element reduces the count
if (bPairs == A.Count)
{
    return bPairs - 1; // Change one element in B to break a pair
}
else
{
    return bPairs + 1; // We can increase the count by changing one element in B
}

}