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

ld pi = 3.141592653589793238462643383;
ld eps = 1e-7;

ld solve(ld ax, ld ay, ld bx, ld by, ld cx, ld cy) {
    ld A = hypot(bx-cx, by-cy), B = hypot(ax-cx, ay-cy), C = hypot(ax-bx, ay-by);
    ld angb = acos(((ax-bx)*(cx-bx)+(ay-by)*(cy-by))/(A*C));
    ld angc = acos(((ax-cx)*(bx-cx)+(ay-cy)*(by-cy))/(A*B));
    if (angb >= pi/2 || angc >= pi/2) return 0;
    ld l = 0, r = A;
    angb /= 2;
    angc /= 2;
    for (int z = 0; z < 100; z++) {
        ld c = (l+r)/2;
        if (2*c+c/tan(angb)+c/tan(angc) > A) r = c;
        else l = c;
    }
    return l;
}

int main() {
    ld x1, y1, x2, y2, x3, y3;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
    ld ans = 0;
    ans = max(ans, solve(x1, y1, x2, y2, x3, y3));
    ans = max(ans, solve(x2, y2, x3, y3, x1, y1));
    ans = max(ans, solve(x3, y3, x1, y1, x2, y2));
    cout << setprecision(20) << ans << endl;
    return 0;
}