#include <stdio.h>
#include <fstream>
using namespace std;

#define N 16

ifstream fin("flip.in");
ofstream fout("flip.out");

int a[N][N];

int main()
{
	int n, m, i, j, l;
	int sum = 0, sumOfLine = 0, max = 0;

	fin >> n >> m;

	for (i = 0; i < n; i++) 
	{
		for (j = 0; j < m; j++)
		{
			fin >> a[i][j];
		}
	}
	
	for (i = 0; i < n * n; i++)
	{
		sum = 0;
		for (j = 0; j < m; j++)
		{
			sumOfLine = 0;
			for (l = 0; l < n; l++)
			{
				sumOfLine += i & (l * l) ? a[l][j] : -a[l][j];
			}
			sum += sumOfLine < 0 ? -sumOfLine : sumOfLine;
		}
		if (sum > max) 
		{
			max = sum;
		}
	}

	fout << max << '\n';

	fin.close();
	fout.close();
	return 0;
}