def main(ctx):
    which = "where" if sys.platform == "win32" else "which"
    if envoy.run(which + " git").status_code != 0:
        click.secho("fatal: git not found in PATH", fg="red")
        sys.exit(1)
    ctx.obj = Hydrogen()
def kth(root, k):
    if k < size(root.left):
        return kth(root.left, k)
    elif k > size(root.left):
        return kth(root.right, k - size(root.left) - 1)
    return root.key