#include <iostream>
#include <climits>
using namespace std;

const int MAXN = 100;

int main() {
    int N;
    int matrix[MAXN][MAXN];
    int rowSum[MAXN];
    
    while (cin >> N) {
        for (int i = 0; i < N; ++i) {
            for (int j = 0; j < N; ++j) {
                cin >> matrix[i][j];
            }
        }

        int maxSum = INT_MIN;

        // 枚举左右边界
        for (int left = 0; left < N; ++left) {
            for (int i = 0; i < N; ++i) {
                rowSum[i] = 0;
            }
            
            for (int right = left; right < N; ++right) {
                // 计算每一行在[left, right]列的和
                for (int i = 0; i < N; ++i) {
                    rowSum[i] += matrix[i][right];
                }

                // 使用Kadane算法求最大子数组和
                int currentSum = 0;
                for (int i = 0; i < N; ++i) {
                    if (currentSum > 0) {
                        currentSum += rowSum[i];
                    } else {
                        currentSum = rowSum[i];
                    }
                    if (currentSum > maxSum) {
                        maxSum = currentSum;
                    }
                }
            }
        }

        cout << maxSum << endl;
    }
    return 0;
}