#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
int a[101][101],i,j,n,minn[101];
bool b[101];
int prim(int s)
{
	int i,j,k,ans=0;
	memset(minn,0x7f,sizeof(minn));
	minn[s]=0;
	memset(b,true,sizeof(b));
	for(i=1;i<=n;i++)
	{
		k=0;
		for(j=1;j<=n;j++)
		if(b[j]&&(minn[j]<minn[k]))
		k=j;
		b[k]=false;
		for(j=1;j<=n;j++)
		if((a[k][j]<minn[j])&&b[j]&&a[k][j]!=0)
		minn[j]=a[k][j];
	}
	for(i=1;i<=n;i++)
	ans+=minn[i];
	return ans;
}
int main()
{
	while(scanf("%d",&n)!=EOF)
	{
		memset(a,0,sizeof(a));
		for(i=1;i<=n;i++)
		for(j=1;j<=n;j++)
		scanf("%d",&a[i][j]);
		int ans;
		ans=prim(1);
		printf("%d\n",ans);
	}
	return 0;
}