#include<bits/stdc++.h>
using namespace std;
double dis(double X1,double Y1,double X2,double Y2){
    return sqrt((X1-X2)*(X1-X2)+(Y1-Y2)*(Y1-Y2));
}
int main(){
    double x1,x2,x3,y1,y2,y3,c=0;
    cin>>x1>>y1>>x2>>y2>>x3>>y3;
    c+=dis(x1,y1,x2,y2)+dis(x1,y1,x3,y3)+dis(x3,y3,x2,y2);
    cout<<c;
    return 0;
}