#include <iostream>
#include <cmath>
#include <cstdlib>
using namespace std;
double max(double x, double y, double z)
{
double r;
if(x >= y)
{
if(x >= z) r = x;
r = z;
}
else // if(x < y)
{
if(y >= z) r = y;
else r = z;
}
return r;
}
double min(double x, double y, double z)
{
double r;
if(x <= y)
{
if(x <= z) r = x;
else r = z;
}
else // if(x > y)
{
if(y <= z) r = y;
else r = z;
}
if(r == 0.0)
{
// чтобы не делить на ноль
cerr << "Error" << endl;
exit(1);
}
return r;
}
int main()
{
double x,y,z,s;
cin >> x >> y >> z;
s = ( max(x,y,z) - 2 * min(x,y,z) ) / ( sin(2.0) + max(x,y,z) / min(x,y,z) );
cout << s << endl;
return 0;
}