/*
#include <stdio.h>
int main()
{
int a, b;
scanf("%d %d",&a, &b);
printf("%d+%d=%d\n",a, b, a+b);
printf("%d-%d=%d\n",a, b, a-b);
printf("%d*%d=%d\n",a, b, a*b);
printf("%d/%d=%d",a, b, a/b);
return 0;
}
*/
/*
#include <stdio.h>
int main()
{
int a, b;
scanf("%d %d", &a, &b);
printf("%.1f",(float)a*b/2);
return 0;
}
*/