#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define fo(i, n) rep(i, 0, n)
#define all(x) std::begin(x), std::end(x)
#define sz(x) int((x).size())
#define F first
#define S second
#define MP make_pair
#define PB push_back
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<vi> vvi;
typedef vector<pii> vpii;
typedef vector<ll> vll;
typedef pair<ll, ll> pll;
typedef vector<vll> vvll;
typedef vector<pll> vpll;
typedef vector<double> vd;
typedef pair<double, double> pdd;
typedef vector<vd> vvd;
typedef vector<pdd> vpdd;

pdd mid(pdd a, pdd b)
{
    return MP((a.F + b.F) / 2, (a.S + b.S) / 2);
}

double sq(double a) { return a * a; }

double dist(pdd a, pdd b)
{
    return sqrt(sq(a.F - b.F) + sq(a.S - b.S));
}

double parans(pdd a, pdd b, pdd c)
{
    pdd m = mid(a, b);
    double correct = dist(m, a);
    double real = dist(m, c);
    return abs(correct - real);
}

signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.badbit | cin.failbit);

    pdd a, b, c;
    cin >> a.F >> a.S;
    cin >> b.F >> b.S;
    cin >> c.F >> c.S;

    double ans = min({parans(a, b, c), parans(b, c, a), parans(a, c, b)});

    cout << fixed << setprecision(10) << ans << endl;
}