#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for(int i=a;i<n;i++)
#define per(i,a,n) for(int i=n-1;i>=a;i--)
typedef long long ll;
typedef double db;
typedef pair<int,int> PII;
typedef vector<int> VI;
const ll mod=1000000007;
const int maxn=155;
const int inf=0x3f3f3f3f;
ll gcd(ll a,ll b){ return b?gcd(b,a%b):a;}
#define ms(a) memset(a,0,sizeof(a))
#define mss(a) memset(a,-1,sizeof(a))
#define msi(a) memset(a,inf,sizeof(a)) 
// head
ll a[maxn][maxn];
ll b[maxn];
ll dp[maxn];
ll maxx=-inf,n;
int main()
{
//	ios::sync_with_stdio(false);
//	cin.tie(0);
//	cout.tie(0);
	cin>>n;
	rep(i,1,n+1)
	rep(j,1,n+1)
	{
		cin>>a[i][j];
	}
	// 压缩 1-1 1-2 1-3 1-4       2-2 2-3 2-4    3-3 3-4  4-4
	// n*(n+1)/2
	rep(i,1,n+1)
	{
		rep(j,i,n+1)
		{
//			b[z]=0;
			rep(z,1,n+1)
			{
				b[z]+=a[j][z];
//				b[z]+=b[z-1];
			}
		}//压缩 
		//长度为n的串，找最大子段和
		rep(z,1,n+1)
		{
			
//			maxx=max(maxx,b[z-1]+b[z]);
			b[z]=max(b[z],b[z-1]+b[z]);
//			dp[z]=max(dp[z-1]+b[z],b[z]);
			maxx=max(b[z],maxx);
//			b[z-1]=0;
		} 
//		b[n]=0;
		memset(b,0,sizeof(b));
//		memset(dp,0,sizeof(dp));
	}
	cout<<maxx<<"\n";
	return 0;
}