#include <stdio.h>
#include <math.h>
int distance(double x1, double x2, double y1, double y2) {
	double m = 0;
	m = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
	double add = 0;
	add = sqrt(m);
	return add;
}
int main() {
	double a1, a2, b1, b2, c1, c2;
	scanf("%lf %lf", &a1, &a2);
	scanf("%lf %lf", &b1, &b2);
	scanf("%lf %lf", &c1, &c2);
	double m, n, j;
	m = distance(a1, a2, b1, b2);
	n = distance(a1, a2, c1, c2);
	j = distance(b1, b2, c1, c2);
	printf("%.2f", m + n + j);
	return 0;
}