#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100;
const int MAXM = 10000;
int n, m; // n个点 m条边
struct Edge
{
    int u, v, w;
};
Edge e[MAXM + 5];
int eCnt;
bool cmp(Edge a, Edge b)
{
    return a.w < b.w;
}
int fa[MAXN + 5];
int findFa(int x)
{
    if (x == fa[x])
        return x;
    return fa[x] = findFa(fa[x]);
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    eCnt = 0;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            eCnt++;
            cin >> e[eCnt].w;
            e[eCnt].u = i;
            e[eCnt].v = j;
        }
    }
    m = eCnt;
    // 排序
    sort(e + 1, e + m + 1, cmp);
    // 并查集初始化
    for (int i = 1; i <= n; i++)
        fa[i] = i;
    // kruskal/避开环
    int ans = 0;
    int cnt = 0;
    for (int i = 1; i <= m; i++)
    {
        // e[i].u <-> e[i].v : e[i].w
        // 如果会构成环，就不选，否则就选
        int faU = findFa(e[i].u);
        int faV = findFa(e[i].v);
        if (faU != faV)
        {
            fa[faU] = faV;
            ans += e[i].w;
            cnt++;
        }
    }
    if (cnt == n - 1)
        cout << ans << "\n";
    else
        cout << "orz\n";
    return 0;
}