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# include <bits/stdc++.h>
using namespace std ;
const int N = 150 ;
int a [ N ] [ N ] ;
int main ( ) {
int n ;
cin > > n ;
for ( int i = 1 ; i < = n ; i + + )
for ( int j = 1 ; j < = n ; j + + ) {
cin > > a [ i ] [ j ] ;
a [ i ] [ j ] + = a [ i - 1 ] [ j ] ; // 按列计算前缀和
}
int ans = INT_MIN ; // 预求最大，先设最小
for ( int i = 1 ; i < = n ; i + + ) // 最底下一行
for ( int k = 1 ; k < = i ; k + + ) { // 往上k行
int dp [ N ] = { 0 } ; // dp[j]表示压缩的矩形前j列的最大累加值
for ( int j = 1 ; j < = n ; j + + ) { // 第j列
int s = a [ i ] [ j ] - a [ i - k ] [ j ] ; // 求压缩的矩形第j列的值
dp [ j ] = max ( dp [ j - 1 ] + s , s ) ; // 动态规划,到j列为止，
ans = max ( ans , dp [ j ] ) ; // 更新答案
}
}
cout < < ans < < endl ; // 愉快AC
return 0 ;
}
