def height(root):
    '''
    Solved with BFS, this is adapt to get shortest distances in tree with edges weight=1
    '''
    explored = {}
    explored[root.info] = 0
    q = deque()
    q.append(root)
    height_tree = 0
    while q:
        v = q.popleft()
        children = []
        if v.left:
            children.append(v.left)
        if v.right:
            children.append(v.right)
        for w in children:
            if not explored.get(w.info) and (w.info not in explored):
                explored[w.info] = explored[v.info] + 1
                height_tree = max(explored[w.info], height_tree)
                q.append(w)
    return height_tree