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题目描述

Given a binary tree, let $n_L$ denotes the number of nodes with only a left child, and $n_R$ the number of nodes with only a right child. The degree of skewness is defined to be $D_s = n_L - n_R$. Your job is to calculate $D_s$ for a given binary tree.

输入格式

Each input file contains one test case. For each case, the first lines gives a positive integer $n$ ($\le 10^3$) which is the number of nodes in the binary tree. The next two lines contain the post-order and in-order traversal sequences of the tree, respectively. The keys are integers from 1 to $n$. All the numbers in a line are seperated by a space.

输出格式

Print in a line the degree of skewness in the format: $D_s$ = $n_L$ - $n_R$

样例

7
1 2 7 5 4 3 6
1 2 3 4 7 5 6

2 = 3 - 1

限制

对于所有的测试用例,限制为400 ms, 64 MB