一直八十分

#include<bits/stdc++.h>
using namespace std;
double x[16],y[16],n;
double min1=INT_MAX;
bool a[16];
void f(int h,int l,double sum,int nn){
	if(sum>=min1) return;
	if(nn==n){
		min1=min(min1,sum);
		return;
	}
	for(int i=1;i<=n;i++){
		if(a[i]==1) continue;
		int x2=x[i],y2=y[i];
		a[i]=1;
		f(x[i],y[i],sum+double(sqrt(double(h-x2)*double(h-x2)+double(l-y2)*double(l-y2))),nn+1);
		a[i]=0;
	}
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++) scanf("%lf%lf",&x[i],&y[i]);
	f(0,0,0,0);
	cout<<fixed<<setprecision(2)<<min1;
	return 0;
}