#include <bits/stdc++.h>
using namespace std;

const int N = 110;
const int M = 10010;

struct Node { //用结构体存储每条边
    int f, t, w;
    bool operator<(const Node &e) const {
        return w < e.w;
    }
} edges[M];

int p[N];

int find(int x) { //并查集找根节点
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}

int n, idx, ans;
int main() {
    scanf("%d", &n);

    //邻接矩阵
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++) {
            int w;
            scanf("%d", &w);
            edges[idx++] = {i, j, w}; //加入当前的边
        }
    sort(edges, edges + idx); //对边权进行排序,注意这里不是优先队列，是谁小谁在前

    for (int i = 1; i <= n; i++) p[i] = i; //并查集初始化
    for (int i = 1; i <= idx; i++) {       //枚举每条边
        int f = find(edges[i].f), t = find(edges[i].t);
        if (f != t) {          //当前两点不连通
            ans += edges[i].w; //更新答案
            p[f] = t;          //让两点变连通
        }
    }
    printf("%d", ans);

    return 0;
}