Domino piling

最新推荐文章于 2020-04-17 22:27:28 发布

原创最新推荐文章于 2020-04-17 22:27:28 发布 · 389 阅读

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本文探讨了一个经典的算法问题——如何在一个M×N的矩形棋盘上放置尽可能多的2×1大小的标准多米诺骨牌，使得每块骨牌完全覆盖两个方格且不相互重叠。文中提供了一种简单的计算方法来确定可以放置的最大多米诺数量。

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A. Domino piling

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given a rectangular board of M × N squares. Also you are given an unlimited number of standard domino pieces of 2 × 1squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:

1. Each domino completely covers two squares.

2. No two dominoes overlap.

3. Each domino lies entirely inside the board. It is allowed to touch the edges of the board.

Find the maximum number of dominoes, which can be placed under these restrictions.

Input

In a single line you are given two integers M and N — board sizes in squares (1 ≤ M ≤ N ≤ 16).

Output

Output one number — the maximal number of dominoes, which can be placed.

Examples

input
2 4

output
4

input
3 3

output
4


#include "stdio.h"
int main()
{
	int m,n,count;
	scanf ("%d%d",&n,&m);
	count=(m*n)/2;
	printf ("%d\n",count);
} 