100分，但是是错的

#include <bits/stdc++.h>

using namespace std;

int n, cnt;
double x[16], y[16], dis[16][16];
double ans = 1e6;

bool vis[16];
void dfs(int deep, int now, double sum) {
	cnt++;
	if (cnt >= 1000000000) {
		cout << fixed<< setprecision(2)<< ans;
		exit(0);
	}
	if (deep > n) {
		if (sum < ans) ans = sum;
		return ;
	}
	for (int i = 1; i <= n; i++)
		if (!vis[i]) {
			double t = sum + dis[now][i];
			if (t >= ans) continue;
			vis[i] = true;
			dfs(deep + 1, i, t);
			vis[i] = false;
		}
}
int main() {
	//freopen(".in", "r", stdin);
	//freopen(".out", "w", stdout);
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n;
	x[0] = 0, y[0] = 0;
	for (int i = 1; i <= n; i++) cin >> x[i]>> y[i];
	for (int i = 0; i <= n; i++)
		for (int j = 0; j <= n; j++)
			dis[i][j] = sqrt((x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]));
	dfs(1, 0, 0);
	cout << fixed<< setprecision(2)<< ans;
	return 0;
}