#include <stdio.h>
#include <math.h>
float triangleArea (float a ,float b,float c);
int main(void) {
float a , b, c ;
scanf("%f %f %f", &a , &b, &c);
printf("your area %f" , triangleArea( a , b, c));
return 0;
}
float triangleArea (float a ,float b,float c) {
float s = (a + b + c) / 2 ;
float m = s *(s- a) * (s -b) * (s -c) ;
return pow(m , .5) ;
}