#include<bits/stdc++.h>
using namespace std;
	double dis (double x1,double y1,double x2,double y2){
		double c;
		c=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
		return c;
	}
int main() {
	double x1,y1,x2,y2,x3,y3,a;
	cin>>x1>>y1>>x2>>y2>>x3>>y3;
	a=dis(x1,x2,y1,y2)+dis(x1,x3,y1,y3)+dis(x2,x3,y2,y3);
	printf("%.2lf\n",a);	
	return 0;
}