#include<stdio.h>
#include<math.h>
#include<stdlib.h>
int main()
{
float a,b,c,s,area;
scanf("%f%f%f",&a,&b,&c);
s=1.0/2*(a+b+c);
area=sqrt(s*(s-a)*(s-b)*(s-c));
printf("a=%7.2f,b=%7.2f,c=%7.2f,s=%7.2f ",a,b,c,s);
printf("area=%7.2f ",area);
return 0;
}