def bin_search_recur(arr: list, left: int, right: int, key: int) -> int:
    """Recursive Binary Search"""
    if right >= left:
        mid = left + (right - left) // 2
        if arr[mid] == key:
            return mid
        if arr[mid] > key:
            return bin_search_recur(arr, left, mid - 1, key)
        else:
            return bin_search_recur(arr, mid + 1, right, key)
    return -1