var inputs = Console.ReadLine().Split(' ');
var a = int.Parse(inputs[0]);
var b = int.Parse(inputs[1]);
var c = int.Parse(inputs[2]);
long s = a + b + c;
var t = (s - a - a) * (s - b - b) * (s - c - c);
var u = (decimal)t / (s * 4);
var pass = u;
decimal fail = 0;
for (var i = 0; i <= 300; i++)
{
    var mid = (pass + fail) / 2;
    if (mid * mid > u) pass = mid;
    else fail = mid;
}
Console.WriteLine(pass);