#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using vi = vector<int>;
using pi = pair <int, int>;
using vpi = vector<pi>;

double calc(pi a, pi b, pi c)
{
    double midx = (a.first + b.first) / 2.0;
    double midy = (a.second + b.second) / 2.0;
    double dx = c.first - midx;
    double dy = c.second - midy;
    double d = sqrt(dx*dx+dy*dy);
    double d2x = a.first - b.first;
    double d2y = a.second - b.second;
    double d2 = sqrt(d2x*d2x+d2y*d2y)/2;
    return abs(d - d2);
}

void solve()
{
    vpi pts(3);

    for (auto& x : pts)
        cin >> x.first >> x.second;

    double res = min({ calc(pts[0], pts[1], pts[2]), calc(pts[0], pts[2], pts[1]), calc(pts[2], pts[1], pts[0]) });

    cout << fixed << setprecision(15) << res << '\n';
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    solve();
    return 0;
}