A full m ary tree with n vertices and i internal vertices has n = mi + 1 vertices and l = m − i + 1 leaves.

How can I proof it?

I know

m ary tree: A rooted tree is called an m ary tree if every internal vertex has no more than m children. The tree is called a full m ary tree if every internal vertex has exactly m children. An m ary tree with m = 2 is called a binary tree

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