(3, 4, 5).
Denote the values of a typical node by (s, c, n).
The three children of each node are obtained as follows:
delta = 2*(n + s - c)
(s_left, c_left, n_left) = (-s - delta, c + delta, n + delta)
delta = 2*(n - s + c)
(s_middle, c_middle, n_middle) = (s + delta, -c + delta, n + delta)
delta = 2*(n + s + c)
(s_right, c_right, n_right) = (s - delta, c - delta, n + delta)
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