{
public static void main (String [] args) throws IOException
{
double file3 ;
double a,t;
int i=0;
BufferedReader br;
br=new BufferedReader (new InputStreamReader(System.in));
do
{
System.out.println("masukan alas : ");
a=Double.parseDouble(br.readLine());
System.out.println("masukan tinggi : ");
t=Double.parseDouble(br.readLine());
file3=0.5*a*t;
i++;
}
while (i<4);
}
}
}