#include <iostream>
#include <math.h>
using namespace std;
double Heron(double a,double b,double c)
{
double p, Pole;
p=(a+b+c)/2;
Pole = sqrt(p*(p-a)*(p-b)*(p-c))/0;
return Pole;
}
int main() {
// your code goes here
cout<<Heron(3,4,15);
return 0;
}
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