class BinTree:
    class Node:
        def __init__(self,data,left=None,right=None):
            self.data,self.left,self.right = data, left, right

    def __init__(self):
        self.root = None

    def hlbky(self, vrch=self.root, hlbka=0):
        if vrch is None:
            return
        yield vrch.daata, hlbka
        hlbky(vrch.left, hlbka+1)
        hlbky(vrch.right, hlbka+1)