#include <stdio.h>
#include <math.h>
double dis(double x1,double y1,double x2,double y2){
	return sqrt(abs((x1-x2)*(x1-x2))+abs((y1-y2)*(y1-y2)));
}
int main(void){
	double x1,x2,x3,y1,y2,y3;
	double dis1,dis2,dis3,c;
	scanf("%lf %lf\n",&x1,&x2);
	scanf("%lf %lf\n",&x2,&y2);
	scanf("%lf %lf",&x3,&y3);
	c=dis(x1,y1,x2,y2)+dis(x1,y1,x3,y3)+dis(x2,y2,x3,y3);
	printf("%.2f",c);	
	return 0;
}