#include<bits/stdc++.h>
using namespace std;
#define ll long long
namespace IO{//by cyffff
	int len=0;
	char ibuf[(1<<21)+1],*iS,*iT,out[(1<<25)+1];
	#if ONLINE_JUDGE
	#define gh() (iS==iT?iT=(iS=ibuf)+fread(ibuf,1,(1<<21)+1,stdin),(iS==iT?EOF:*iS++):*iS++)
 	#else
	#define gh() getchar()
	#endif
	#define reg register
	inline int read(){
		reg char ch=gh();
		reg int x=0;
		reg char t=0;
		while(ch<'0'||ch>'9')   t|=ch=='-',ch=gh();
		while(ch>='0'&&ch<='9') x=x*10+(ch^48),ch=gh();
		return t?-x:x;
	}
	inline void putc(char ch){
		out[len++]=ch;
	}
	template<class T>
	inline void write(T x){
		if(x<0)putc('-'),x=-x;
		if(x>9)write(x/10);
		out[len++]=x%10+48;
	}
	inline void flush(){
		fwrite(out,1,len,stdout);
		len=0;
	}
	inline char getc(){
		char ch=gh();
		while(ch<'A'||ch>'Z') ch=gh();
		return ch;
	}
}
using IO::read;
using IO::write;
using IO::flush;
using IO::getc;
using IO::putc;
#define pii pair<int,int>
#define mpr make_pair
#define fir first
#define sec second
const int N=400+10,INF=1e9+10;
int n,d[N][N];
struct node{
	int u,v,w;
	inline friend bool operator<(const node &a,const node &b){
		return a.w>b.w;
	}
};
vector<node>vec;
vector<int>b[N];
bitset<N>a[N],vis[2][N];
inline void dfs(int x,int i,int d){
	bitset<N>tp=a[x]&(~vis[!d][i]);
	for(int j=tp._Find_first();j!=tp.size();j=tp._Find_next(j))
		vis[!d][i][j]=vis[!d][j][i]=1;
	for(int j=tp._Find_first();j!=tp.size();j=tp._Find_next(j))
		dfs(j,i,!d);
}
inline void add(int u,int v){
	bitset<N>tp=vis[0][u]&~vis[1][v];
	for(int i=tp._Find_first();i!=tp.size();i=tp._Find_next(i))
		vis[1][i][v]=vis[1][v][i]=1,dfs(v,i,1);
	tp=vis[1][u]&~vis[0][v];
	for(int i=tp._Find_first();i!=tp.size();i=tp._Find_next(i))
		vis[0][i][v]=vis[0][v][i]=1,dfs(v,i,0);
	a[u][v]=a[v][u]=1;
}
int dfn[N],low[N],stk[N],top,bel[N],tim,inc[N],bc;
inline void Tarjan(int x){
	dfn[x]=low[x]=++tim,stk[++top]=x,inc[x]=1;
	for(auto t:b[x]){
		if(!dfn[t]) Tarjan(t),low[x]=min(low[x],low[t]);
		else if(inc[t]) low[x]=min(low[x],dfn[t]);
	}
	if(dfn[x]==low[x]){
		bc++;
		while(1){
			int p=stk[top--];
			inc[p]=0,bel[p]=bc;
			if(p==x) break;
		}
	}
}
inline void clear(){
	for(int i=1;i<=n*2;i++)
		b[i].clear();
	for(int i=1;i<=n*2;i++)
		dfn[i]=bel[i]=inc[i]=0;
	tim=bc=0;
}
inline bool check(int x){
	for(int i=1;i<=n;i++)
		for(int j=a[i]._Find_first();j!=a[i].size();j=a[i]._Find_next(j))
			b[i].push_back(j+n);
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			if(d[i][j]>x)
				b[i+n].push_back(j);
	for(int i=1;i<=n*2;i++)
		if(!dfn[i])
			Tarjan(i);
	bool fl=1;
	for(int i=1;i<=n;i++)
		if(bel[i]==bel[i+n])
			fl=0;
	clear();
	return fl;
}
int main(){
	n=read();
	for(int i=1;i<=n;i++)
		for(int j=i+1;j<=n;j++)
			vec.push_back({i,j,d[i][j]=d[j][i]=read()});
	if(n<=2) return puts("0"),0;
	sort(vec.begin(),vec.end());
	int ans=INF*2;
	for(auto e:vec){
		int u=e.u,v=e.v;
		if(!vis[1][u][v]){
			int L=0,R=vec.size()-1,res=-1;
			if(check(0)) res=0;
			else{
				while(L<=R){
					int mid=L+R>>1;
					if(check(vec[mid].w)) L=mid+1,res=vec[mid].w;
					else R=mid-1;
				}
			}
			if(res!=-1) ans=min(ans,e.w+res);
		}
		if(vis[0][u][v]) break;
		add(u,v);
	}
	write(ans);
	flush();
}