#include <iostream>
 
using namespace std;
int mainrqaewsfaef()
{
    int w;/* 长 */
    int h;/* 宽 */
    int des=0;
    cin >> w >> h;
    int arr[100][100] = { 0 };
    /* 填二维数组 */
    for (int i=0;i<h;i++)
    {
        for (int j=0;j<w;j+=2)
        {
            if ((j%4)==0)
            {
                arr[i][j +1] = 1;
                arr[i][j] = 1;
            }
            else
            {
                arr[i][j + 1] = 0;
                arr[i][j] = 0;
            }

        }
    }
    for (int i = 2; i < h; i+=4)
    {
        for (int j = 0; j < w; j += 2)
        {
            if ((j % 4) == 0)
            {
                arr[i][j + 1] =0;
                arr[i + 1][j + 1] = 0;
                arr[i][j] = 0;
                arr[i + 1][j] = 0;
            }
            else
            {
                arr[i][j + 1] = 1;
                arr[i + 1][j + 1] = 1;
                arr[i][j] = 1;
                arr[i + 1][j] = 1;
            }

        }
    }
    for (int i = 0; i < h; i++)
    {
        for (int j = 0; j < w; j++)
        {
             if (arr[i][j]==1)
             {
                 des++;
             }
        }
    }
    cout << des<<endl;
    system("pause"); 
    return 0;
}