#include <stdio.h>
#include <math.h>

int main()
{
    int k1, k2;
    int a1, b1, a2, b2;

    scanf("%d %d %d %d %d %d", &k1, &k2, &a1, &a2, &b1, &b2);

    int vec11 = k1 - b1, vec12 = k2 - b2;
    int vec21 = b1 - a1, vec22 = b2 - a2;
    int scal2 =  - vec11 * vec21 - vec12 * vec22;

    vec11 = k1 - a1;
    vec12 = k2 - a2;
    int scal1 = vec11 * vec21 + vec12 * vec22;

    if (scal1 <= 0 || scal2 <= 0)
    {
        float len1 = sqrt(vec11 * vec11 + vec12 * vec12);
        vec11 = k1 - b1;
        vec12 = k2 - b2;
        float len2 = sqrt(vec11 * vec11 + vec12 * vec12);
        printf("%f", ((len1 < len2) ? len1 : len2));
        return 0;
    }

    float mult = vec11 * vec22 - vec21 * vec12;
    float len = sqrt(vec21 * vec21 + vec22 * vec22);
    printf("%f", (fabs(mult / len)));

}