#include <iostream>
#include <cstring>
#define inf 0x3f3f3f
using namespace std;
const int N = 110;
int graph[N][N];
int n;
typedef long long ll;
ll res = 0;
int dist[N];
bool st[N];
void read(){
    cin >> n;
    for(int i = 1; i <= n; i ++ ){
        for(int j = 1; j <= n; j ++ )   cin >> graph[i][j];
    }
}
void prim(){
    memset(dist, inf, sizeof dist);
    dist[1] = 0;
    for(int i = 1; i <= n; i ++ ){
        int nxt = -1;
        for(int j = 1; j <= n; j ++ ){
            if(!st[j] && (nxt == -1 || dist[nxt] > dist[j]))    nxt = j;
        }
        st[nxt] = true;
        res += dist[nxt];
        for(int i = 1; i <= n; i ++ ){
            dist[i] = min(dist[i], graph[nxt][i]);
        }
    }
}
int main(){
    read();
    prim();
    cout << res << endl;
    return 0;
}