P17265 [AtCoder] In K-city, there are n streets running east-west, and m streets running north-south. Each street running east-west and each street running north-south cross each other. We will call the smal
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题目描述

In K-city, there are n streets running east-west, and m streets running north-south. Each street running east-west and each street running north-south cross each other. We will call the smallest area that is surrounded by four streets a block. How many blocks there are in K-city?

-----Constraints-----
- 2 ≤ n, m ≤ 100

-----Input-----
Input is given from Standard Input in the following format:
n m

-----Output-----
Print the number of blocks in K-city.

-----Sample Input-----
3 4

-----Sample Output-----
6

There are six blocks, as shown below:

输入格式

见题面

输出格式

见题面

样例输入
3 4
样例输出
6