/* -*- coding: utf-8 -*-
 *
 * 3151.cc:  No.3151 natural math of  inscribed circle - yukicoder
 */

#include<cstdio>
#include<cmath>
#include<algorithm>

using namespace std;

/* main */

int main() {
  int a, b, c;
  scanf("%d%d%d", &a, &b, &c);

  // Helon's formula:
  //   Let d=(a+b+c)/2 -> sqrt(d(d-a)(d-b)(d-c))

  double d = 0.5 * (a + b + c);
  double s = sqrt(d * (d - a) * (d - b) * (d - c));

  // r*a/2+r*b/2+r*c/2=s -> r*(a+b+c)/2=s -> r=s*2/(a+b+c)
  double r = s / d;

  printf("%.15lf\n", r);
  
  return 0;
}