poj 2605 Simple game on a grid

Simple game on a grid

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 847		Accepted: 435

Description

There is an infinite grid and an m*n rectangle of stones on it (1 <= m,n <= 1000). The stones are located in the knots of the grid.

A following game for a single player is being played. One stone can jump over another along a vertical or a horizontal line. A stone which had been overjumped is taken away. The purpose of the game is to minimize number of stones on a grid.

Given a pair of numbers m and n separated with one space in an input file you are to write a program which should determine a minimal number of the stones left on the grid.

Input

Numbers m and n separated by space.

Output

The minimal number of the stones left on the grid.

Sample Input

3 4

Sample Output

2

#include <stdio.h>

int main()
{
    int m,n,t;
    while(scanf("%d%d",&m,&n)!=EOF)
    {
        if(n>m) {t=n;n=m;m=t;}
        if(n==1 || n==2) printf("%d\n",(m+1)/2);
        else if(n%3==0 || m%3==0) printf("2\n");
        else printf("1\n");
    }
    return 0;
}