#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    vector<int>x(3);
    vector<int>y(3);
    for (int i = 0; i < 3; ++i) {
      cin >> x[i] >> y[i];
    }
    vector<double>edge(3);
    for (int i = 0; i < 3; ++i) {
        double dx = x[i] - x[(i+1)%3];
        double dy = y[i] - y[(i+1)%3];
        edge[i] = sqrt(pow(dx, 2) + pow(dy, 2));
    }
    sort(edge.begin(), edge.end());
    double area = (x[0]-x[2]) * (y[1]-y[2]) - (y[0]-y[2]) * (x[1]-x[2]);
    double h = abs(area) / edge[2];

    // (e[0]+e[1]+e[2]+2*h)x=e[2]*h を満たす
    double a = edge[0] + edge[1] + edge[2] + h*2;
    double ans = edge[2] * h / a;
    cout << setprecision(16) << ans;
    return 0;
}