#include<cstdio>
 

#include<vector>
#include<queue>
using namespace std;
struct Edge {
	int from, to;
	int weight;
	Edge(int f, int t, int w) :from(f), to(t), weight(w) {}
	bool operator <(const Edge& e)const { return this->weight > e.weight; }
};
// prim 求MST
int prim(vector<vector<int>>
 
& vec) {
	priority_queue<Edge> myQueue;
	for (int i = 1; i < vec.size(); ++i)
		myQueue.emplace(0,i,vec[0][i]);
	vector<int> visit(vec.size(), 0);
	visit[0] = 1;// 標記第一個節點
	int visitCount = 1;// 已經被加入到生成樹中節點個數
	int MSTWeight = 0;// 最小生成樹的權值
	while (visitCount < vec.size() && !myQueue.
 
empty()){
		Edge edge = myQueue.top();
		myQueue.pop();
		if (visit[edge.to] == 1)// 若該邊指向的另外一個點已被訪問，則跳過。
			continue;
		visit[edge.to] = 1;     // 標記訪問記號
		++visitCount;
		MSTWeight += edge.weight;
		for (int i = 0; i < vec.size(); ++i){
			if (visit[i] == 0)
				myQueue.emplace(edge.to,i,vec[edge.to][i]);// 把與edge.to相連的邊全部加入到最小堆中
		}
	}
	return MSTWeight;
}

int main() {
	int edgeLen;
	while (scanf("%d",&edgeLen)!=EOF){
		vector<vector<int> > graph;
		int rowCount = edgeLen;
		while (0 < rowCount){
			vector<int> tmpVec;
			int tmpColCount = edgeLen;
			while (0 < tmpColCount--){
				int tmp;
				scanf("%d", &tmp);
				tmpVec.emplace_back(tmp);
			}
			graph.emplace_back(tmpVec);
			--rowCount;
		}
		printf("%d\n", prim(graph));
	}
	return 0;
}