# tree = [chr(x) for x in range(64,75)]
# tree[0] = ''
# root = 1
# n = len(tree)
# 왼쪽자식 2*i
# 오른쪽자식 2*i + 1
# 부모노드 i//2
# def preorder(root):
#     print(tree[root])
#     for i in range(h) :
#         if
tree = ['','+','*','-','/',3,4,5,1,2]
