#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#define int long long
#define ld long double
#define vec vector
#define all(m) (m).begin(), (m).end()
#define forn(i,n) for(int i=0;i<(n);i++)

using namespace std;

struct P {
    ld x,y;
};

ld dist(P p1, P p2) {
    ld dx = p2.x - p1.x;
    ld dy = p2.y - p1.y;
    ld dst = sqrt(dx*dx + dy*dy);
    return dst;
}


void solve() {
    vec<P> pnts(3);
    forn(i, 3) {
        cin>>pnts[i].x>>pnts[i].y;
    }

    ld ans = 20000;
    forn(i,3) {
        P p1(-200, -200), p2(-200,-200), p3(-200,-200);
        forn(j,3) {
            if (i == j) {
                p3 = pnts[j];
                continue;
            }

            if (p1.x == -200 && p1.y == -200)
                p1 = pnts[j];
            else
                p2 = pnts[j];
        }


        ld dx = p2.x - p1.x;
        ld dy = p2.y - p1.y;
        ld dst = dist(p1, p2);
        P cent;
        cent.x = p1.x + dx/2.0L;
        cent.y = p1.y + dy/2.0L;

        ld cur_ans = fabs(dist(p3, cent) - dst/2.0L);
        ans = min(ans, cur_ans);
    }
    cout<<fixed<<setprecision(15)<<ans<<endl;
}

signed main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int tt = 1;
    // cin>>tt;
    while (tt--)
        solve();
    return 0;
}