#include<bits/stdc++.h>
using namespace std;
double s(int x1,int y1,int x2,int y2){
    return sqrt(pow(x1-x2,2)+pow(y1-y2,2));
}
int main(){
    double x1,x2,x3;
    double y1,y2,y3;
    cin>>x1>>y1;
    cin>>x2>>y2;
    cin>>x3>>y3;
    printf("%.2lf",s(x1,y1,x2,y2)+s(x1,y1,x3,y3)+s(x2,y2,x3,y3));
}

最后一个点出486.21（right:486.20