#include<iostream>

#include<cstdio>

#include<string>

#include<algorithm>

typedef long long ll;

using namespace std;

struct Node {

    int x, y, w;

    friend bool operator < (const Node& a, const Node& b) {

        return a.w < b.w;

    }

};

Node a[];

int pre[];

int Find(int x) {

    return pre[x] == x ? x : pre[x] = Find(pre[x]);

}

int main() {

    int n, k, cnt = ;

    scanf("%d", &n);

    for (int i = ; i < n; i++) {

        pre[i] = i;

        for(int j=;j<n;j++){

        scanf("%d", &k);

          if (j > i) {   //矩阵只需判断一半

              a[cnt].x = i;

              a[cnt].y = j;

              a[cnt++].w = k;

          }

        }

    }

    sort(a, a + cnt);

    int ans = ;

    int p = ;

    for (int i = ; i <cnt; i++) {

        if (Find(a[i].x) != Find(a[i].y)) {

            ans += a[i].w;

            pre[Find(a[i].x)] = a[i].y;

            p++;

            if (p == n - ) break;

        }

    }

    printf("%d\n", ans);

    return ;

}

#include<iostream>

#include<cstdio>

#include<string>

#include<algorithm>

typedef long long ll;

using namespace std;

struct Node {

    int x, y;

    double w;

    friend bool operator < (const Node& a, const Node& b) {

        return a.w < b.w;

    }

};

Node a[];    //数组注意开大

int pre[];

double x[];

double y[];

int Find(int x) {

    return pre[x] == x ? x : pre[x] = Find(pre[x]);

}

double dis(double x1, double y1, double x2, double y2) {

    return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));

}

int main() {

    int T,c;

    scanf("%d", &T);

    while (T--) {

        int cnt = ;

        scanf("%d", &c);

        for (int i = ; i < c; i++) {

            pre[i] = i;

            scanf("%lf%lf", &x[i], &y[i]);

            for (int j = ; j < i; j++) {

                double dist = dis(x[i], y[i], x[j], y[j]);

                if(dist>=10.0&&dist<=1000.0){

                a[cnt].x = i;

                a[cnt].y = j;

                //printf("%d %d\n", a[cnt].x, a[cnt].y);

                a[cnt++].w = dist;}

            }

        }

        sort(a, a + cnt);

        double ans = ;

        int p = ;

        for (int i = ; i < cnt; i++) {

            if (Find(a[i].x) != Find(a[i].y)) {

                ans += a[i].w ;

                pre[Find(a[i].x)] = a[i].y;

                p++;

                if (p == c - ) break;

            }

        }

        if (p == c - ) printf("%.1f\n", ans*);

        else printf("oh!\n");

    }

    return ;

}