#include <stdio.h>
#include <conio.h>
main()
{
	float d,f,g;
	printf("Input D :");
	scanf("%f" ,&d);
	printf("Input F :");
	scanf("%f" ,&f);
	g = 0.5*(d*f);
	printf("\nResult : %2.f",g);
	printf("\nBy Sarunchana surasiang No.25");
	
}