#include <bits/stdc++.h>
using namespace std;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define IREP(i, n) IFOR(i,0,n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(),v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x) distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x) distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL<<(n))
#define bit_exist(x, n) ((x >> n) & 1)
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v) cout << #v << "=" << endl; REP(i_debug, v.size()){ cout << v[i_debug] << ","; } cout << endl;
#define mdebug(m) cout << #m << "=" << endl; REP(i_debug, m.size()){ REP(j_debug, m[i_debug].size()){ cout << m[i_debug][j_debug] << ","; } cout << endl;}
#define pb push_back
#define f first
#define s second
#define int long long
#define INF 1000000000000000000
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for (auto &x : v) is >> x; return is; }
template<typename T> ostream &operator<<(ostream &os, vector<T> &v){ for(int i = 0; i < v.size(); i++) { cout << v[i]; if(i != v.size() - 1) cout << endl; }; return os; }
template<typename T> void Out(T x) { cout << x << endl; }
template<typename T1, typename T2> void Ans(bool f, T1 y, T2 n) { if(f) Out(y); else Out(n); }

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

//int dx[4] = {1,0,-1,0};
//int dy[4] = {0,1,0,-1};
//char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
//const int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod

void normalize(double &x, double &y){
    double r = sqrt(x * x + y * y);
    x /= r; y /= r;
}

double calctheta(double &x, double &y){
    double theta = acos(x);
    if(y >= 0) return theta;
    else return 2.0 * M_PI - theta;
}

void rotate(double &x, double &y, double theta){
    double x0 = x, y0 = y;
    x = x0 * cos(theta) - y0 * sin(theta);
    y = x0 * sin(theta) + y0 * cos(theta);
}



signed main(){

    vector<double> x(3), y(3);
    REP(i, 3) cin >> x[i] >> y[i];

    double X1 = x[1] - x[0], X2 = x[2] - x[0];
    double Y1 = y[1] - y[0], Y2 = y[2] - y[0];
    double S = abs(X1 * Y2 - X2 * Y1);
    double R = 0.0;
    REP(i, 3){
        double dX = x[(i + 1) % 3] - x[i];
        double dY = y[(i + 1) % 3] - y[i];
        R += sqrt(dX * dX + dY * dY);
    }
    double r0 = 0.0, r1 = S / R;
    
    while(r1 - r0 > max(1.0e-11, r1 * 1.0e-11)){
        double r = (r0 + r1) / 2;

        bool f = false;
        vector<double> x0(3), y0(3);

        REP(i, 3){
            double dx1 = x[(i + 1) % 3] - x[i];
            double dy1 = y[(i + 1) % 3] - y[i];
            double dx2 = x[(i + 2) % 3] - x[i];
            double dy2 = y[(i + 2) % 3] - y[i];

            normalize(dx1, dy1);
            normalize(dx2, dy2);
            double theta1 = calctheta(dx1, dy1);
            double theta2 = calctheta(dx2, dy2);
            double theta = theta2 - theta1;

            if(theta < 0) theta += 2.0 * M_PI;

            if(theta > M_PI){
                swap(dx1, dx2);
                swap(dy1, dy2);
                theta = 2.0 * M_PI - theta;
            }

            rotate(dx1, dy1, theta / 2.0);
            double D = r / sin(theta / 2.0);
            x0[i] = x[i] + dx1 * D, y0[i] = y[i] + dy1 * D;
        }

        REP(i, 3){
            double dx = x0[(i + 1) % 3] - x0[i], dy = y0[(i + 1) % 3] - y0[i];
            double d = sqrt(dx * dx + dy * dy);
            if(d >= 2 * r) f = true;
        }

        if(f) r0 = r;
        else r1 = r;
    }
    Out(r0);

    return 0;
}


Measured memory_bytes: 640