#include<iostream>
#include<cstdio>
#include<cctype>
using namespace std;
const int maxn=1510;
const int inf=0xfffffff;
int n;
int g[maxn][maxn];
int minw[maxn];
bool vis[maxn];
inline void in(int &x){
    x=0;int f=1;char t=getchar();
    while(!isdigit(t)){if(t=='-')f=-1;t=getchar();}
    while(isdigit(t)){x=x*10+t-48;t=getchar();}
    x*=f;
}
inline int prim(){
	fill(minw,minw+n,inf);
	minw[0]=0;
	int ans=0;
	while(1){
		int v=-1;
		for(int u=0;u<n;u++){
			if(!vis[u]&&(v==-1||minw[u]<minw[v])) v=u;
		}
		if(v==-1) break;
		vis[v]=1;
		ans+=minw[v];
		for(int u=0;u<n;u++) minw[u]=min(minw[u],g[v][u]);
	}
	return ans;
}
inline int work(){
	in(n);
	for(int i=0;i<n;i++)
	 for(int j=0;j<n;j++)
	  in(g[i][j]);
	printf("%d",prim());
}
inline int mian(){
	freopen("wire.in","r",stdin);
	freopen("wire.out","w",stdout);
	work();
}
int miku=mian();
int main(){;}