//POJ1258
#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;

const int MAX = 501;
const int COST_MAX = 0x7FFFFFFF;
int prime(int G[][MAX], int N)
{
	int sum = 0;
	int v[MAX];
	memset(v,0,MAX);
	v[0] = 1;
	int cal = 0;
	while( cal != N-1)
	{
		int min = COST_MAX;
		int x = 0;
		int y = 0;
		for( int i = 0; i != N; ++i)
		{
			if(v[i]==0) continue;
			for(int j = 1; (j != N); ++j)
			{
				if(v[j]==1) continue;
				if( G[i][j] && G[i][j]<min )
				{
					min = G[i][j];
					x = i;
					y = j;
				}
			}
		}
		if(min != COST_MAX)
		{
			sum += min;
			v[x] = 1;
			v[y] = 1;
			++cal;
		}
	}
	return sum;
}

int main()
{
	int N;
	int G[MAX][MAX];
	while(cin>>N)
	{
		memset( G, 0, MAX*MAX );
		for(int i = 0; i != N; ++i)
			for(int j = 0; j != N; ++j)
				cin>>G[i][j];

		cout<<prime(G,N)<<endl;

	}
	return 0;
}