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

#define sqr(a) ((a)*(a))
typedef long double ld;


ld d(ld x, ld y, ld a, ld b, ld c)
{
    return (abs(a*x + b*y + c) / sqrt(a*a + b*b));
}



int main()

{
    ifstream cin("input.txt");

    int x, y, x1, y1, x2, y2;
    long double a, b, c;

    cin >> x >> y >> x1 >> y1 >> x2 >> y2;

    a = (y2 - y1);
    b = (x1 - x2);
    c = (x2*y1 - x1*y2);

    cout << fixed << setprecision(60) << abs(d(x, y, a, b, c)) << endl;

    return 0;
}