import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

enum inf3 = 1_001_001_001;
enum inf6 = 1_001_001_001_001_001_001L;
enum mod = 1_000_000_007L;


void main() {
    auto x = new double[](3);
    auto y = new double[](3);
    iota(3).each!(i => scan(x[i], y[i]));
    auto l = iota(3).map!(i => hypot(abs(x[(i+1) % 3] - x[i]), y[(i+1) % 3] - y[i])).array;
    l.sort();
    debug {
        writeln(l);
    }
    auto s = (l[0] + l[1] + l[2]) / 2;
    auto m = sqrt(s * (s - l[0]) * (s - l[1]) * (s - l[2]));
    auto R = 2 * m / (l[0] + l[1] + l[2]);

    double ok = 0, ng = 1000;

    bool check(double r) {
        double x = l[2] * (1 - r / R);
        return 2*r <= x;
    }

    foreach (i ; 0 .. 1000) {
        double mid = (ok + ng) / 2;
        (check(mid) ? ok : ng) = mid;
    }

    writefln("%.12f", ok);
}






void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}

void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
